/* =========================================================
   levietlong.com homepage
   1. Reset
   2. Variables
   3. Base
   4. Header
   5. Hero
   6. Services
   7. Statistics
   8. About
   9. Contact
   10. Footer
   11. Responsive
   ========================================================= */

/* 1. Reset */
*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    text-size-adjust: 100%;
}

body,
h1,
h2,
h3,
p,
blockquote,
ul {
    margin: 0;
}

ul {
    padding: 0;
    list-style: none;
}

img {
    display: block;
    max-width: 100%;
}

button,
a {
    -webkit-tap-highlight-color: transparent;
}

button,
input,
textarea,
select {
    font: inherit;
}

/* 2. Variables */
:root {
    --color-navy-950: #041735;
    --color-navy-900: #06275b;
    --color-navy-800: #0a3476;
    --color-blue-700: #1d4ed8;
    --color-blue-600: #2563eb;
    --color-blue-500: #3b82f6;
    --color-blue-100: #dbeafe;
    --color-blue-50: #eff6ff;
    --color-soft: #f4f8ff;
    --color-white: #ffffff;
    --color-text: #0f2347;
    --color-muted: #52647e;
    --color-line: #dce5f2;
    --color-success: #10b981;
    --color-orange: #f97316;
    --color-ice: #0ea5e9;
    --color-leaf: #65a30d;
    --color-purple: #7c3aed;
    --color-rose: #e11d48;
    --color-dongiap-bg: #17123d;
    --color-dongiap-purple: #6d4aff;
    --color-dongiap-gold: #c79a45;
    --font-main: 'Nunito Sans', 'Be Vietnam Pro', Arial, Helvetica, sans-serif;
    --font-number: 'Be Vietnam Pro', 'Nunito Sans', Arial, Helvetica, sans-serif;
    --radius-sm: 12px;
    --radius-md: 18px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --shadow-sm: 0 10px 25px rgba(15, 35, 71, 0.07);
    --shadow-md: 0 18px 50px rgba(15, 35, 71, 0.11);
    --shadow-blue: 0 18px 42px rgba(37, 99, 235, 0.22);
    --container: 1240px;
    --header-height: 78px;
    --transition: 0.25s ease;
}

/* 3. Base */
body {
    min-width: 320px;
    color: var(--color-text);
    font-family: var(--font-main);
    background:
        radial-gradient(circle at 12% 2%, rgba(37, 99, 235, 0.10), transparent 32%),
        radial-gradient(circle at 86% 8%, rgba(14, 165, 233, 0.11), transparent 30%),
        linear-gradient(180deg, #f8fbff 0%, #ffffff 48%, #f5f9ff 100%);
    line-height: 1.65;
    overflow-x: hidden;
}

a {
    color: inherit;
    text-decoration: none;
}

a:focus-visible,
button:focus-visible {
    outline: 3px solid rgba(59, 130, 246, 0.55);
    outline-offset: 3px;
}

.container {
    width: min(100% - 48px, var(--container));
    margin-inline: auto;
}

.skip-link {
    position: fixed;
    left: 16px;
    top: 16px;
    z-index: 9999;
    padding: 10px 14px;
    border-radius: 999px;
    background: var(--color-white);
    color: var(--color-navy-900);
    box-shadow: var(--shadow-sm);
    transform: translateY(-150%);
    transition: transform var(--transition);
}

.skip-link:focus {
    transform: translateY(0);
}

.section {
    padding: 72px 0;
}

.section-heading {
    max-width: 780px;
    margin: 0 auto 34px;
    text-align: center;
}

.section-kicker,
.eyebrow {
    color: var(--color-blue-600);
    font-weight: 800;
    letter-spacing: 0.04em;
}

.section-kicker {
    margin-bottom: 6px;
    font-size: 14px;
}

.section-heading h2 {
    color: var(--color-navy-900);
    font-size: clamp(30px, 3.2vw, 44px);
    font-weight: 900;
    line-height: 1.18;
    letter-spacing: -0.045em;
}

.section-heading p {
    margin-top: 12px;
    color: var(--color-muted);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 18px;
    border: 1px solid transparent;
    border-radius: 14px;
    font-weight: 800;
    line-height: 1;
    transition: transform var(--transition), box-shadow var(--transition), background-color var(--transition), border-color var(--transition);
    gap: 9px;
}

.btn:hover {
    transform: translateY(-2px);
}

.btn:active {
    transform: translateY(0);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-blue-600), var(--color-blue-700));
    color: var(--color-white);
    box-shadow: var(--shadow-blue);
}

.btn-primary:hover {
    box-shadow: 0 20px 48px rgba(37, 99, 235, 0.30);
}

.btn-soft {
    border-color: #c7d8f6;
    background: rgba(255, 255, 255, 0.74);
    color: var(--color-blue-700);
}

.btn-soft:hover {
    border-color: var(--color-blue-500);
    background: #ffffff;
}

.btn-small {
    min-height: 44px;
    padding-inline: 16px;
    font-size: 14px;
}

/* 4. Header */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    min-height: var(--header-height);
    background: linear-gradient(90deg, var(--color-navy-950), var(--color-navy-900) 54%, #0b55bc);
    color: #ffffff;
    box-shadow: 0 12px 32px rgba(4, 23, 53, 0.16);
    transition: box-shadow var(--transition), background-color var(--transition);
}

.site-header.is-scrolled {
    box-shadow: 0 16px 44px rgba(4, 23, 53, 0.25);
}

.header-inner {
    min-height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 13px;
    min-width: 0;
}

.brand-logo-wrap {
    position: relative;
    width: 48px;
    height: 48px;
    flex: 0 0 48px;
}

.brand-logo-img,
.brand-logo-fallback {
    width: 48px;
    height: 48px;
    border-radius: 15px;
}

.brand-logo-img {
    object-fit: cover;
}

.brand-logo-fallback {
    display: none;
    place-items: center;
    color: #ffffff;
    font-family: var(--font-number);
    font-size: 27px;
    font-weight: 900;
    background: linear-gradient(145deg, #60a5fa, #1d4ed8 66%, #173c9f);
    box-shadow: inset 0 1px 0 rgba(255,255,255,0.30), 0 10px 22px rgba(37,99,235,0.32);
}

.brand-text strong {
    display: block;
    color: #ffffff;
    font-family: var(--font-number);
    font-size: 21px;
    font-weight: 900;
    line-height: 1.05;
    letter-spacing: -0.035em;
}

.brand-text small {
    display: block;
    margin-top: 4px;
    color: #cfe3ff;
    font-size: 12.5px;
    white-space: nowrap;
}

.primary-nav {
    display: flex;
    align-items: center;
    gap: 7px;
}

.nav-link,
.nav-contact {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    border-radius: 999px;
    color: #e9f2ff;
    font-weight: 800;
    font-size: 14px;
    transition: color var(--transition), background-color var(--transition), border-color var(--transition);
}

.nav-link {
    padding: 0 15px;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: 4px;
    width: 0;
    height: 3px;
    border-radius: 999px;
    background: #93c5fd;
    transform: translateX(-50%);
    transition: width var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: #ffffff;
    background: rgba(255, 255, 255, 0.08);
}

.nav-link.active::after {
    width: 30px;
}

.nav-contact {
    gap: 8px;
    margin-left: 10px;
    padding: 0 17px;
    border: 1px solid rgba(255,255,255,0.35);
    background: rgba(255,255,255,0.08);
}

.nav-contact:hover {
    background: rgba(255,255,255,0.15);
    border-color: rgba(255,255,255,0.52);
}

.nav-toggle {
    display: none;
    width: 46px;
    height: 46px;
    border: 1px solid rgba(255,255,255,0.32);
    border-radius: 14px;
    background: rgba(255,255,255,0.10);
    cursor: pointer;
}

.nav-toggle span {
    display: block;
    width: 20px;
    height: 2px;
    margin: 5px auto;
    border-radius: 999px;
    background: #ffffff;
    transition: transform var(--transition), opacity var(--transition);
}

body.nav-open .nav-toggle span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

body.nav-open .nav-toggle span:nth-child(2) {
    opacity: 0;
}

body.nav-open .nav-toggle span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* 5. Hero */
.hero {
    position: relative;
    overflow: hidden;
    padding: 70px 0 66px;
    border-bottom: 1px solid rgba(220, 229, 242, 0.95);
    background:
        linear-gradient(105deg, rgba(255,255,255,0.94) 0%, rgba(244,248,255,0.96) 46%, rgba(219,234,254,0.82) 100%);
}

.hero-bg-pattern {
    position: absolute;
    inset: 0;
    pointer-events: none;
    opacity: 0.44;
    background-image:
        radial-gradient(circle at 18px 18px, rgba(37,99,235,0.13) 1px, transparent 1px),
        linear-gradient(120deg, transparent 0%, transparent 62%, rgba(37,99,235,0.06) 62%, rgba(37,99,235,0.06) 100%);
    background-size: 34px 34px, 100% 100%;
}

.hero::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    bottom: -1px;
    height: 48px;
    background: linear-gradient(178deg, transparent 0%, transparent 48%, #ffffff 49%, #ffffff 100%);
}

.hero-grid {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: minmax(0, 0.92fr) minmax(430px, 1.08fr);
    align-items: center;
    gap: 48px;
}

.eyebrow {
    font-size: 18px;
    line-height: 1.2;
}

.hero h1 {
    margin-top: 14px;
    color: var(--color-navy-900);
    font-family: var(--font-number);
    font-size: clamp(48px, 6vw, 82px);
    font-weight: 900;
    line-height: 1;
    letter-spacing: -0.075em;
}

.hero-description {
    max-width: 610px;
    margin-top: 22px;
    color: #33455f;
    font-size: clamp(16px, 1.35vw, 19px);
}

.hero-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 28px;
}

.hero-badges span {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    min-height: 44px;
    padding: 0 14px;
    border: 1px solid rgba(191, 219, 254, 0.95);
    border-radius: 14px;
    background: rgba(255,255,255,0.78);
    color: #0d2f66;
    box-shadow: 0 10px 24px rgba(37,99,235,0.07);
    font-weight: 800;
    font-size: 14px;
    backdrop-filter: blur(10px);
}

.hero-badges i {
    color: var(--color-blue-600);
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 30px;
}

.hero-visual {
    min-width: 0;
}

.hero-image-card {
    position: relative;
    overflow: hidden;
    min-height: 420px;
    border: 1px solid rgba(147, 197, 253, 0.82);
    border-radius: 34px;
    background: #eaf4ff;
    box-shadow: 0 30px 80px rgba(30, 80, 160, 0.17);
}

.hero-image-card::before {
    content: '';
    position: absolute;
    inset: 0;
    z-index: 1;
    background: linear-gradient(180deg, rgba(255,255,255,0) 58%, rgba(6,39,91,0.08) 100%);
    pointer-events: none;
}

.hero-image-card img {
    width: 100%;
    height: 100%;
    min-height: 420px;
    object-fit: cover;
}

.image-hidden {
    display: none;
}

.image-placeholder {
    display: none;
    width: 100%;
    min-height: 420px;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 8px;
    color: var(--color-blue-700);
    background: linear-gradient(145deg, #eaf4ff, #ffffff);
}

.image-placeholder i {
    font-size: 58px;
}

.image-placeholder strong {
    font-family: var(--font-number);
    font-size: 26px;
}

.image-placeholder span {
    color: var(--color-muted);
}

/* 6. Services */
.services-section {
    background:
        radial-gradient(circle at 7% 8%, rgba(37,99,235,0.07), transparent 28%),
        linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
}

.business-section {
    padding-top: 28px;
    background:
        radial-gradient(circle at 92% 4%, rgba(124,58,237,0.055), transparent 26%),
        linear-gradient(180deg, #f8fbff 0%, #ffffff 100%);
}

.utilities-section .section-heading,
.business-section .section-heading {
    margin-bottom: 30px;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.service-card {
    position: relative;
    min-height: 328px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    padding: 24px;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-lg);
    background: rgba(255,255,255,0.94);
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.service-card:hover {
    transform: translateY(-5px);
    border-color: rgba(59,130,246,0.42);
    box-shadow: var(--shadow-md);
}

.service-card:focus-within {
    border-color: var(--color-blue-500);
}

.service-ornament {
    position: absolute;
    inset: 0;
    pointer-events: none;
    background:
        radial-gradient(circle at 88% 2%, rgba(37,99,235,0.10), transparent 34%),
        linear-gradient(180deg, rgba(255,255,255,0.90), rgba(255,255,255,0));
}

.service-head {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 16px;
}

.service-icon {
    width: 62px;
    height: 62px;
    flex: 0 0 62px;
    display: grid;
    place-items: center;
    border-radius: 18px;
    color: #ffffff;
    font-size: 28px;
    box-shadow: 0 15px 30px rgba(15,35,71,0.16);
}

.service-badge {
    display: inline-flex;
    align-items: center;
    min-height: 30px;
    padding: 0 10px;
    border-radius: 999px;
    background: var(--service-soft, #eff6ff);
    color: var(--service-color, var(--color-blue-600));
    border: 1px solid rgba(37,99,235,0.16);
    font-size: 12px;
    font-weight: 900;
    white-space: nowrap;
}

.service-number {
    position: absolute;
    right: 22px;
    bottom: 16px;
    z-index: 0;
    color: rgba(15,35,71,0.035);
    font-family: var(--font-number);
    font-size: 92px;
    font-weight: 900;
    line-height: 1;
}

.service-card h3,
.service-domain,
.service-card p,
.service-button {
    position: relative;
    z-index: 1;
}

.service-card h3 {
    color: #071f49;
    font-size: 18px;
    font-weight: 900;
    line-height: 1.28;
    letter-spacing: -0.03em;
}

.service-domain {
    display: inline-flex;
    margin-top: 5px;
    color: var(--service-color, var(--color-blue-600));
    font-size: 14px;
    font-weight: 900;
    word-break: break-word;
}

.service-domain:hover {
    text-decoration: underline;
}

.service-card p {
    margin-top: 14px;
    color: var(--color-muted);
    font-size: 14.5px;
    line-height: 1.65;
}

.service-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    align-self: flex-start;
    gap: 8px;
    min-height: 42px;
    margin-top: auto;
    padding: 0 15px;
    border: 1px solid color-mix(in srgb, var(--service-color, var(--color-blue-600)) 40%, #ffffff);
    border-radius: 12px;
    color: var(--service-color, var(--color-blue-600));
    background: #ffffff;
    font-size: 14px;
    font-weight: 900;
    transition: background-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.service-button:hover {
    transform: translateY(-2px);
    background: var(--service-soft, #eff6ff);
    box-shadow: 0 10px 22px rgba(15,35,71,0.08);
}

.service-button[aria-disabled="true"] {
    cursor: default;
}

.theme-blue { --service-color: var(--color-blue-600); --service-soft: #eff6ff; }
.theme-green { --service-color: #059669; --service-soft: #ecfdf5; }
.theme-orange { --service-color: var(--color-orange); --service-soft: #fff7ed; }
.theme-ice { --service-color: var(--color-ice); --service-soft: #f0f9ff; }
.theme-leaf { --service-color: var(--color-leaf); --service-soft: #f7fee7; }
.theme-purple { --service-color: var(--color-purple); --service-soft: #f5f3ff; }
.theme-rose { --service-color: var(--color-rose); --service-soft: #fff1f2; }
.theme-dongiap { --service-color: var(--color-dongiap-gold); --service-soft: #f7f3ff; }

.theme-blue .service-icon { background: linear-gradient(145deg, #60a5fa, #1d4ed8); }
.theme-green .service-icon { background: linear-gradient(145deg, #34d399, #059669); }
.theme-orange .service-icon { background: linear-gradient(145deg, #fb923c, #f97316); }
.theme-ice .service-icon { background: linear-gradient(145deg, #7dd3fc, #2563eb); }
.theme-leaf .service-icon { background: linear-gradient(145deg, #84cc16, #16a34a); }
.theme-purple .service-icon { background: linear-gradient(145deg, #a78bfa, #7c3aed); }
.theme-rose .service-icon { background: linear-gradient(145deg, #fb7185, #e11d48); }

.featured-card {
    color: #ffffff;
    border-color: rgba(199,154,69,0.42);
    background:
        radial-gradient(circle at 82% 12%, rgba(199,154,69,0.20), transparent 24%),
        radial-gradient(circle at 18% 100%, rgba(109,74,255,0.25), transparent 30%),
        linear-gradient(145deg, #100d2d 0%, #17123d 52%, #0a234f 100%);
    box-shadow: 0 18px 48px rgba(23,18,61,0.22);
}

.featured-card::before {
    content: '';
    position: absolute;
    inset: 14px;
    border: 1px solid rgba(199,154,69,0.28);
    border-radius: 18px;
    pointer-events: none;
}

.featured-card .service-ornament {
    background:
        radial-gradient(circle at 50% 30%, transparent 0 24px, rgba(199,154,69,0.16) 25px 26px, transparent 27px 44px, rgba(199,154,69,0.10) 45px 46px, transparent 47px),
        linear-gradient(90deg, rgba(255,255,255,0.04) 1px, transparent 1px),
        linear-gradient(0deg, rgba(255,255,255,0.04) 1px, transparent 1px);
    background-size: 190px 190px, 42px 42px, 42px 42px;
    opacity: 0.72;
}

.featured-card .service-icon {
    background: linear-gradient(145deg, #2e2665, #17123d);
    color: #f6d794;
    border: 1px solid rgba(199,154,69,0.35);
}

.featured-card h3,
.featured-card .service-domain,
.featured-card p {
    color: #ffffff;
}

.featured-card .service-domain {
    color: #f0c878;
}

.featured-card p {
    color: rgba(255,255,255,0.78);
}

.featured-card .service-number {
    color: rgba(255,255,255,0.05);
}

.featured-card .service-button {
    background: rgba(255,255,255,0.05);
    border-color: rgba(199,154,69,0.58);
    color: #f8d98e;
}

.featured-card:hover {
    border-color: rgba(199,154,69,0.70);
    box-shadow: 0 26px 60px rgba(23,18,61,0.34), 0 0 0 1px rgba(199,154,69,0.10) inset;
}

.is-coming .service-button {
    opacity: 0.92;
}


.business-card {
    min-height: 306px;
    background: rgba(255,255,255,0.96);
}

.business-card .service-icon {
    width: 58px;
    height: 58px;
    flex-basis: 58px;
    font-size: 25px;
}

.business-grid .service-card h3 {
    font-size: 17.5px;
}

.utilities-section + .business-section {
    margin-top: -24px;
}

/* 7. Statistics */
.stats-section {
    padding: 18px 0 26px;
    background: linear-gradient(180deg, #ffffff 0%, #ffffff 100%);
}

.stats-panel {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    overflow: hidden;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-lg);
    background: rgba(255,255,255,0.94);
    box-shadow: var(--shadow-sm);
}

.stat-item {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    min-height: 104px;
    padding: 22px 18px;
    border-right: 1px solid #e5edf8;
}

.stat-item:last-child {
    border-right: 0;
}

.stat-icon {
    display: grid;
    width: 48px;
    height: 48px;
    place-items: center;
    color: var(--color-blue-600);
    font-size: 31px;
}

.stat-item strong {
    display: block;
    color: var(--color-blue-600);
    font-family: var(--font-number);
    font-size: clamp(26px, 2.8vw, 35px);
    font-weight: 900;
    line-height: 1;
}

.stat-item small {
    display: block;
    margin-top: 5px;
    color: var(--color-muted);
    font-weight: 700;
}

/* 8. About */
.about-contact-section {
    padding-top: 32px;
    background: linear-gradient(180deg, #ffffff 0%, #f5f9ff 100%);
}

.about-contact-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: 22px;
}

.info-card {
    position: relative;
    overflow: hidden;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-lg);
    background: rgba(255,255,255,0.94);
    box-shadow: var(--shadow-sm);
    padding: 30px;
}

.info-card::after {
    content: '';
    position: absolute;
    right: -80px;
    top: -90px;
    width: 210px;
    height: 210px;
    border-radius: 50%;
    background: rgba(37,99,235,0.07);
    pointer-events: none;
}

.card-title-line {
    width: 38px;
    height: 3px;
    margin-bottom: 12px;
    border-radius: 999px;
    background: var(--color-blue-600);
}

.info-card h2 {
    color: var(--color-navy-900);
    font-size: 26px;
    font-weight: 900;
    letter-spacing: -0.035em;
}

.about-body {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 156px 1fr;
    gap: 28px;
    align-items: center;
    margin-top: 22px;
}

.teacher-photo,
.teacher-placeholder {
    width: 156px;
    height: 156px;
    border-radius: 50%;
}

.teacher-photo {
    overflow: hidden;
    border: 1px solid #cfe0f6;
    background: linear-gradient(145deg, #eaf4ff, #ffffff);
    box-shadow: 0 16px 34px rgba(15,35,71,0.10);
}

.teacher-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center 28%;
}

.teacher-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-blue-600);
    font-size: 58px;
    background: linear-gradient(145deg, #eff6ff, #ffffff);
}

.about-text p {
    color: #40516a;
}

.check-list {
    display: grid;
    gap: 9px;
    margin: 16px 0 20px;
}

.check-list li {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    color: #243956;
    font-weight: 600;
}

.check-list li::before {
    content: '\f00c';
    display: inline-grid;
    place-items: center;
    width: 21px;
    height: 21px;
    flex: 0 0 21px;
    margin-top: 2px;
    border-radius: 50%;
    background: var(--color-blue-600);
    color: #ffffff;
    font-family: 'Font Awesome 6 Free';
    font-size: 11px;
    font-weight: 900;
}

/* 9. Contact */
.contact-layout {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 170px;
    gap: 18px;
    align-items: center;
    margin-top: 20px;
}

.contact-list {
    display: grid;
    gap: 13px;
    margin-bottom: 22px;
}

.contact-list li {
    display: flex;
    align-items: center;
    gap: 12px;
    color: #2b3d56;
    font-weight: 600;
}

.contact-list i {
    display: grid;
    width: 34px;
    height: 34px;
    place-items: center;
    flex: 0 0 34px;
    border-radius: 12px;
    background: var(--color-blue-50);
    color: var(--color-blue-600);
}

.contact-list a:hover {
    color: var(--color-blue-600);
    text-decoration: underline;
}

.contact-visual {
    min-height: 170px;
}

.contact-visual img {
    width: 100%;
    height: 170px;
    object-fit: contain;
}

.envelope-placeholder {
    display: none;
    width: 100%;
    height: 170px;
    align-items: center;
    justify-content: center;
    border-radius: 24px;
    background: linear-gradient(145deg, #eff6ff, #ffffff);
    color: var(--color-blue-600);
    font-size: 60px;
}

/* 10. Footer */
.site-footer {
    background:
        radial-gradient(circle at 20% 0%, rgba(59,130,246,0.20), transparent 28%),
        linear-gradient(90deg, var(--color-navy-950), var(--color-navy-900));
    color: #dbeafe;
    padding: 38px 0 26px;
}

.footer-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.25fr) minmax(280px, 0.75fr);
    gap: 36px;
    align-items: center;
}

.footer-quote {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.footer-quote > i {
    color: #60a5fa;
    font-size: 42px;
}

.footer-quote blockquote {
    max-width: 650px;
    color: #ffffff;
    font-size: clamp(18px, 2vw, 23px);
    font-style: italic;
    font-weight: 600;
    line-height: 1.55;
}

.footer-quote cite {
    display: block;
    margin-top: 8px;
    color: #bfdbfe;
    font-style: normal;
    font-size: 15px;
    font-weight: 800;
}

.footer-connect {
    justify-self: end;
}

.footer-connect h2 {
    margin-bottom: 14px;
    color: #ffffff;
    font-size: 18px;
}

.social-links {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.social-links a {
    display: grid;
    width: 44px;
    height: 44px;
    place-items: center;
    border: 1px solid rgba(255,255,255,0.16);
    border-radius: 50%;
    background: rgba(255,255,255,0.10);
    color: #ffffff;
    transition: transform var(--transition), background-color var(--transition);
}

.social-links a:hover {
    transform: translateY(-2px);
    background: rgba(255,255,255,0.18);
}

.social-links span {
    font-size: 11px;
    font-weight: 900;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    gap: 18px;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.14);
    color: #bfdbfe;
    font-size: 14px;
}

.footer-bottom nav {
    display: flex;
    flex-wrap: wrap;
    gap: 22px;
}

.footer-bottom a:hover {
    color: #ffffff;
    text-decoration: underline;
}



/* 4b. Header tinh chỉnh theo phong cách hệ thống điểm */
.site-header {
    background: rgba(255, 255, 255, 0.96);
    color: #0f2f6e;
    border-bottom: 1px solid #dbe8fb;
    box-shadow: 0 10px 28px rgba(15, 47, 110, 0.08);
    backdrop-filter: blur(14px);
}

.site-header.is-scrolled {
    background: rgba(255, 255, 255, 0.985);
    box-shadow: 0 16px 40px rgba(15, 47, 110, 0.13);
}

.brand-logo-wrap.brand-logo-academic {
    position: relative;
    display: grid;
    place-items: center;
    width: 50px;
    height: 50px;
    flex: 0 0 50px;
    border-radius: 17px;
    background:
        radial-gradient(circle at 32% 22%, rgba(255,255,255,0.78), transparent 28%),
        linear-gradient(145deg, #3b82f6 0%, #1d4ed8 54%, #0f2f6e 100%);
    color: #ffffff;
    box-shadow: 0 12px 28px rgba(29, 78, 216, 0.22), inset 0 1px 0 rgba(255,255,255,0.42);
    overflow: hidden;
}

.brand-logo-wrap.brand-logo-academic::after {
    content: '';
    position: absolute;
    right: -12px;
    bottom: -12px;
    width: 34px;
    height: 34px;
    border-radius: 999px;
    border: 8px solid rgba(255,255,255,0.18);
}

.brand-cap {
    position: relative;
    z-index: 1;
    font-size: 25px;
    line-height: 1;
    filter: drop-shadow(0 2px 3px rgba(15,47,110,0.22));
}

.brand-text strong {
    color: #0f2f6e;
    font-family: var(--font-number);
    font-weight: 900;
    letter-spacing: -0.025em;
}

.brand-text small {
    color: #5d7190;
    font-weight: 700;
}

.nav-link,
.nav-contact {
    color: #29415f;
    font-weight: 800;
}

.nav-link::after {
    background: #2563eb;
}

.nav-link:hover,
.nav-link.active {
    color: #1d4ed8;
    background: #eaf2ff;
}

.nav-contact {
    color: #ffffff;
    background: linear-gradient(135deg, #2563eb, #1d4ed8);
    border: 1px solid rgba(37, 99, 235, 0.92);
    box-shadow: 0 10px 22px rgba(37, 99, 235, 0.18);
}

.nav-contact:hover {
    color: #ffffff;
    background: linear-gradient(135deg, #1d4ed8, #1742b5);
    border-color: #1742b5;
}

.nav-toggle {
    border-color: #cfe0ff;
    background: #f8fbff;
}

.nav-toggle span {
    background: #1d4ed8;
}

.hero h1,
.about-hero-copy h1 {
    font-family: var(--font-number);
}

.hero-description,
.about-lead,
.section-heading p,
.card-content p,
.about-hero-copy p:not(.eyebrow):not(.about-lead) {
    font-weight: 500;
}

/* 11. Responsive */
@media (max-width: 1199px) {
    :root { --container: 1120px; }

    .hero-grid {
        grid-template-columns: minmax(0, 0.95fr) minmax(400px, 1.05fr);
        gap: 34px;
    }

    .services-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

@media (max-width: 991px) {
    :root { --header-height: 72px; }

    .container {
        width: min(100% - 36px, var(--container));
    }

    .nav-toggle {
        display: block;
    }

    .primary-nav {
        position: absolute;
        left: 18px;
        right: 18px;
        top: calc(100% + 10px);
        display: grid;
        gap: 6px;
        padding: 14px;
        border: 1px solid rgba(191,219,254,0.36);
        border-radius: 22px;
        background: rgba(6, 39, 91, 0.98);
        box-shadow: 0 22px 52px rgba(4,23,53,0.32);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-8px);
        transition: opacity var(--transition), visibility var(--transition), transform var(--transition);
    }

    body.nav-open .primary-nav {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }

    .nav-link,
    .nav-contact {
        justify-content: flex-start;
        width: 100%;
        margin: 0;
        padding: 0 14px;
    }

    .nav-link.active::after {
        display: none;
    }

    .hero {
        padding: 52px 0 50px;
    }

    .hero-grid {
        grid-template-columns: 1fr;
    }

    .hero-copy {
        max-width: 720px;
    }

    .hero-image-card,
    .hero-image-card img,
    .image-placeholder {
        min-height: 360px;
    }

    .services-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .stats-panel {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .stat-item:nth-child(2) {
        border-right: 0;
    }

    .stat-item:nth-child(-n + 2) {
        border-bottom: 1px solid #e5edf8;
    }

    .about-contact-grid {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .footer-connect {
        justify-self: start;
    }
}

@media (max-width: 767px) {
    .container {
        width: min(100% - 28px, var(--container));
    }

    .brand-text small {
        display: none;
    }

    .brand-logo-wrap,
    .brand-logo-img,
    .brand-logo-fallback {
        width: 42px;
        height: 42px;
    }

    .brand-text strong {
        font-size: 18px;
    }

    .hero {
        padding-top: 42px;
    }

    .hero h1 {
        letter-spacing: -0.06em;
    }

    .hero-actions .btn {
        width: 100%;
    }

    .hero-badges span {
        min-height: 42px;
        font-size: 13px;
    }

    .hero-image-card,
    .hero-image-card img,
    .image-placeholder {
        min-height: 280px;
        border-radius: 24px;
    }

    .section {
        padding: 52px 0;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .service-card {
        min-height: 286px;
    }

    .stats-panel {
        grid-template-columns: 1fr;
    }

    .stat-item {
        justify-content: flex-start;
        border-right: 0;
        border-bottom: 1px solid #e5edf8;
    }

    .stat-item:last-child {
        border-bottom: 0;
    }

    .about-body,
    .contact-layout {
        grid-template-columns: 1fr;
    }

    .contact-visual {
        max-width: 220px;
    }

    .footer-bottom {
        flex-direction: column;
    }
}

@media (max-width: 479px) {
    .container {
        width: min(100% - 22px, var(--container));
    }

    .hero-description {
        font-size: 15.5px;
    }

    .hero-badges {
        gap: 9px;
    }

    .hero-badges span {
        width: 100%;
    }

    .service-card,
    .info-card {
        padding: 20px;
        border-radius: 20px;
    }

    .service-head {
        margin-bottom: 14px;
    }

    .service-icon {
        width: 56px;
        height: 56px;
        flex-basis: 56px;
        font-size: 25px;
    }

    .teacher-photo,
    .teacher-placeholder {
        width: 138px;
        height: 138px;
    }

    .footer-quote {
        gap: 14px;
    }

    .footer-quote > i {
        font-size: 32px;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.001ms !important;
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
    }
}


/* =========================================================
   About page additions
   ========================================================= */
body.about-page {
    background:
        radial-gradient(circle at 12% 2%, rgba(37, 99, 235, 0.12), transparent 30%),
        radial-gradient(circle at 86% 9%, rgba(16, 185, 129, 0.08), transparent 32%),
        linear-gradient(180deg, #f8fbff 0%, #ffffff 44%, #f4f8ff 100%);
}

.about-page .nav-link.active::after {
    width: 100%;
}

.about-hero-section {
    position: relative;
    padding: 76px 0 58px;
    overflow: hidden;
    background: linear-gradient(135deg, #f4f8ff 0%, #ffffff 52%, #eaf3ff 100%);
    border-bottom: 1px solid #dce5f2;
}

.about-hero-bg {
    position: absolute;
    inset: 0;
    pointer-events: none;
    opacity: 0.65;
    background-image:
        radial-gradient(circle at 12% 20%, rgba(37, 99, 235, 0.13), transparent 26%),
        radial-gradient(circle at 82% 14%, rgba(14, 165, 233, 0.16), transparent 24%),
        linear-gradient(90deg, rgba(6, 39, 91, 0.05) 1px, transparent 1px),
        linear-gradient(180deg, rgba(6, 39, 91, 0.05) 1px, transparent 1px);
    background-size: auto, auto, 54px 54px, 54px 54px;
}

.about-hero-grid {
    position: relative;
    display: grid;
    grid-template-columns: minmax(0, 1.05fr) minmax(360px, 0.75fr);
    gap: 42px;
    align-items: center;
}

.about-hero-copy h1 {
    margin: 10px 0 14px;
    color: var(--color-navy-900);
    font-size: clamp(44px, 6.2vw, 78px);
    font-weight: 900;
    line-height: 1.02;
    letter-spacing: -0.065em;
}

.about-lead {
    color: var(--color-text);
    font-size: clamp(18px, 1.8vw, 22px);
    font-weight: 700;
    line-height: 1.55;
}

.about-hero-copy p:not(.eyebrow):not(.about-lead) {
    margin-top: 14px;
    max-width: 760px;
    color: var(--color-muted);
    font-size: 16.5px;
}

.about-hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 28px;
}

.profile-card {
    position: relative;
    overflow: hidden;
    padding: 28px;
    border: 1px solid rgba(220, 229, 242, 0.95);
    border-radius: 30px;
    background:
        linear-gradient(180deg, rgba(255,255,255,0.96), rgba(244,248,255,0.96));
    box-shadow: var(--shadow-md);
}

.profile-card::before {
    content: '';
    position: absolute;
    top: -90px;
    right: -90px;
    width: 220px;
    height: 220px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(37,99,235,0.16), transparent 64%);
}

.profile-photo-wrap {
    position: relative;
    width: 164px;
    height: 164px;
    margin: 0 auto 18px;
    border-radius: 50%;
    padding: 7px;
    background: linear-gradient(135deg, #ffffff, #dbeafe);
    box-shadow: 0 18px 40px rgba(15, 35, 71, 0.13);
}

.profile-photo-wrap img,
.profile-placeholder {
    width: 100%;
    height: 100%;
    border-radius: 50%;
}

.profile-photo-wrap img {
    object-fit: cover;
    object-position: center 28%;
}

.profile-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    background:
        radial-gradient(circle at 50% 28%, #ffffff 0%, #dbeafe 44%, #bfdbfe 100%);
    color: var(--color-blue-700);
    font-size: 66px;
}

.profile-info {
    position: relative;
    text-align: center;
}

.profile-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
    padding: 8px 12px;
    border-radius: 999px;
    background: #eff6ff;
    color: var(--color-blue-700);
    font-size: 13px;
    font-weight: 900;
}

.profile-info h2 {
    color: var(--color-navy-900);
    font-size: 26px;
    line-height: 1.2;
    letter-spacing: -0.035em;
}

.profile-info p {
    margin-top: 8px;
    color: var(--color-muted);
}

.profile-metrics {
    position: relative;
    display: grid;
    gap: 10px;
    margin-top: 22px;
}

.profile-metrics div {
    display: grid;
    grid-template-columns: 78px 1fr;
    gap: 12px;
    align-items: center;
    padding: 13px 14px;
    border: 1px solid #dce5f2;
    border-radius: 16px;
    background: rgba(255,255,255,0.84);
}

.profile-metrics strong {
    color: var(--color-blue-700);
    font-family: var(--font-number);
    font-size: 30px;
    line-height: 1;
}

.profile-metrics span {
    color: var(--color-muted);
    font-size: 13.5px;
    font-weight: 700;
    line-height: 1.35;
}

.about-nav-section {
    padding: 18px 0 0;
}

.about-quick-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.about-quick-nav a {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    min-height: 42px;
    padding: 0 14px;
    border: 1px solid #dce5f2;
    border-radius: 999px;
    background: #ffffff;
    color: var(--color-navy-900);
    font-size: 14px;
    font-weight: 800;
    box-shadow: 0 8px 18px rgba(15, 35, 71, 0.05);
    transition: transform var(--transition), border-color var(--transition), color var(--transition);
}

.about-quick-nav a:hover {
    transform: translateY(-2px);
    border-color: var(--color-blue-500);
    color: var(--color-blue-700);
}

.about-split-section {
    padding-top: 56px;
}

.about-two-col {
    display: grid;
    grid-template-columns: minmax(0, 0.95fr) minmax(360px, 0.75fr);
    gap: 34px;
    align-items: center;
}

.align-left {
    margin: 0;
    text-align: left;
}

.align-left p + p {
    margin-top: 12px;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
}

.mini-card,
.tool-item,
.business-card {
    border: 1px solid #dce5f2;
    background: rgba(255,255,255,0.94);
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.mini-card:hover,
.tool-item:hover,
.business-card:hover {
    transform: translateY(-4px);
    border-color: #bfdbfe;
    box-shadow: var(--shadow-md);
}

.mini-card {
    min-height: 154px;
    padding: 22px;
    border-radius: 22px;
}

.mini-card span,
.tool-item span,
.business-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 54px;
    height: 54px;
    border-radius: 18px;
    background: linear-gradient(135deg, var(--color-blue-600), var(--color-blue-700));
    color: #ffffff;
    font-size: 24px;
    box-shadow: 0 12px 26px rgba(37,99,235,0.18);
}

.mini-card h3,
.tool-item h3,
.business-card h3 {
    margin-top: 14px;
    color: var(--color-navy-900);
    font-size: 18px;
    line-height: 1.3;
    letter-spacing: -0.02em;
}

.education-section {
    background: linear-gradient(180deg, rgba(244,248,255,0.7), rgba(255,255,255,0.96));
}

.timeline {
    position: relative;
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 16px;
}

.timeline-item {
    position: relative;
    min-height: 210px;
    padding: 24px;
    border: 1px solid #dce5f2;
    border-radius: 24px;
    background: #ffffff;
    box-shadow: var(--shadow-sm);
}

.timeline-year {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 76px;
    height: 38px;
    padding: 0 14px;
    border-radius: 999px;
    background: var(--color-blue-50);
    color: var(--color-blue-700);
    font-family: var(--font-number);
    font-weight: 900;
}

.timeline-item h3 {
    margin-top: 18px;
    color: var(--color-navy-900);
    font-size: 18px;
    line-height: 1.32;
}

.timeline-item p {
    margin-top: 8px;
    color: var(--color-muted);
    font-size: 14.5px;
}

.research-panel {
    display: grid;
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1fr);
    gap: 32px;
    align-items: center;
    padding: 38px;
    border: 1px solid #dce5f2;
    border-radius: 32px;
    background:
        radial-gradient(circle at 100% 0%, rgba(37,99,235,0.10), transparent 36%),
        #ffffff;
    box-shadow: var(--shadow-md);
}

.research-copy h2,
.direction-card h2,
.about-cta-card h2 {
    color: var(--color-navy-900);
    font-size: clamp(28px, 3vw, 42px);
    font-weight: 900;
    line-height: 1.18;
    letter-spacing: -0.045em;
}

.research-copy p:not(.section-kicker),
.direction-card p,
.about-cta-card p {
    margin-top: 12px;
    color: var(--color-muted);
}

.topic-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.topic-cloud span {
    display: inline-flex;
    align-items: center;
    min-height: 42px;
    padding: 0 14px;
    border: 1px solid #dce5f2;
    border-radius: 999px;
    background: #f8fbff;
    color: var(--color-navy-900);
    font-size: 14px;
    font-weight: 800;
}

.tool-list {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 16px;
}

.tool-item {
    min-height: 210px;
    padding: 22px;
    border-radius: 22px;
}

.tool-item:nth-child(2) span { background: linear-gradient(135deg, #10b981, #059669); }
.tool-item:nth-child(3) span { background: linear-gradient(135deg, #7c3aed, #4f46e5); }
.tool-item:nth-child(4) span { background: linear-gradient(135deg, #c79a45, #7c3aed); }
.tool-item:nth-child(5) span { background: linear-gradient(135deg, #e11d48, #fb7185); }

.business-section {
    background: linear-gradient(180deg, #ffffff, #f4f8ff);
}

.business-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.business-card {
    min-height: 320px;
    padding: 24px;
    border-radius: 24px;
}

.business-card:nth-child(1) .business-icon { background: linear-gradient(135deg, #65a30d, #16a34a); }
.business-card:nth-child(2) .business-icon { background: linear-gradient(135deg, #0ea5e9, #2563eb); }
.business-card:nth-child(3) .business-icon { background: linear-gradient(135deg, #f97316, #fb923c); }
.business-card:nth-child(4) .business-icon { background: linear-gradient(135deg, #e11d48, #f43f5e); }

.business-card p {
    margin-top: 12px;
    color: var(--color-muted);
    font-size: 14.5px;
}

.direction-section {
    padding: 76px 0;
}

.direction-card,
.about-cta-card {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(320px, 0.65fr);
    gap: 34px;
    align-items: center;
    border-radius: 32px;
    box-shadow: var(--shadow-md);
}

.direction-card {
    padding: 42px;
    background:
        radial-gradient(circle at 100% 0%, rgba(199,154,69,0.18), transparent 34%),
        linear-gradient(135deg, var(--color-navy-950), var(--color-navy-900));
    color: #ffffff;
}

.direction-card .section-kicker,
.direction-card h2 {
    color: #ffffff;
}

.direction-card p {
    color: #dbeafe;
}

.direction-card blockquote {
    margin: 0;
    padding: 26px;
    border: 1px solid rgba(255,255,255,0.18);
    border-radius: 24px;
    background: rgba(255,255,255,0.08);
    color: #ffffff;
    font-size: 18px;
    font-weight: 700;
    line-height: 1.65;
}

.direction-card cite {
    display: block;
    margin-top: 14px;
    color: #bfdbfe;
    font-style: normal;
    font-size: 14px;
}

.about-contact-cta {
    padding-top: 0;
}

.about-cta-card {
    padding: 36px;
    border: 1px solid #dce5f2;
    background: #ffffff;
}

.about-cta-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 12px;
}

@media (max-width: 1180px) {
    .tool-list {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .business-grid,
    .timeline {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 991px) {
    .about-hero-grid,
    .about-two-col,
    .research-panel,
    .direction-card,
    .about-cta-card {
        grid-template-columns: 1fr;
    }

    .about-hero-section {
        padding-top: 56px;
    }

    .profile-card {
        max-width: 560px;
    }

    .course-grid {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    .direction-card blockquote {
        font-size: 16px;
    }

    .about-cta-actions {
        justify-content: flex-start;
    }
}

@media (max-width: 767px) {
    .about-quick-nav {
        justify-content: flex-start;
        overflow-x: auto;
        padding-bottom: 4px;
        flex-wrap: nowrap;
    }

    .about-quick-nav a {
        white-space: nowrap;
    }

    .course-grid,
    .timeline,
    .tool-list,
    .business-grid {
        grid-template-columns: 1fr;
    }

    .research-panel,
    .direction-card,
    .about-cta-card,
    .profile-card {
        padding: 24px;
        border-radius: 24px;
    }

    .business-card,
    .tool-item,
    .timeline-item {
        min-height: auto;
    }
}

@media (max-width: 479px) {
    .about-hero-actions,
    .about-cta-actions {
        flex-direction: column;
    }

    .about-hero-actions .btn,
    .about-cta-actions .btn {
        width: 100%;
    }

    .profile-metrics div {
        grid-template-columns: 60px 1fr;
    }

    .profile-metrics strong {
        font-size: 24px;
    }
}


/* Mobile header tinh chỉnh */
@media (max-width: 991px) {
    .primary-nav {
        border: 1px solid #dbe8fb;
        background: rgba(255, 255, 255, 0.985);
        box-shadow: 0 22px 52px rgba(15, 47, 110, 0.16);
    }

    .primary-nav .nav-link,
    .primary-nav .nav-contact {
        color: #29415f;
        background: transparent;
        border-color: transparent;
        box-shadow: none;
    }

    .primary-nav .nav-link:hover,
    .primary-nav .nav-link.active {
        color: #1d4ed8;
        background: #eaf2ff;
    }

    .primary-nav .nav-contact {
        color: #ffffff;
        background: linear-gradient(135deg, #2563eb, #1d4ed8);
        border-color: #2563eb;
        justify-content: center;
        margin-top: 4px;
    }
}

@media (max-width: 767px) {
    .brand-logo-wrap.brand-logo-academic {
        width: 44px;
        height: 44px;
        flex-basis: 44px;
        border-radius: 15px;
    }
    .brand-cap { font-size: 22px; }
}


/* =========================================================
   v4. Header đồng bộ với hệ thống điểm + timeline học vấn
   ========================================================= */
.site-header {
    background: rgba(255, 255, 255, 0.965);
    border-bottom: 1px solid #dbe5f3;
    color: #10233f;
    box-shadow: 0 10px 26px rgba(15, 47, 110, 0.06);
    backdrop-filter: blur(10px);
}

.site-header.is-scrolled {
    background: rgba(255, 255, 255, 0.985);
    box-shadow: 0 14px 34px rgba(15, 47, 110, 0.10);
}

.brand-logo-wrap.brand-logo-academic {
    width: 42px;
    height: 42px;
    flex: 0 0 42px;
    border-radius: 14px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: #1d4ed8;
    color: #ffffff;
    box-shadow: 0 8px 18px rgba(29, 78, 216, 0.18);
}

.brand-logo-wrap.brand-logo-academic::after {
    display: none;
}

.brand-logo-wrap.brand-logo-academic i {
    font-size: 20px;
    line-height: 1;
}

.brand-text strong {
    color: #0f2f6e;
    font-family: var(--font-number);
    font-size: 20px;
    font-weight: 900;
    line-height: 1.16;
    letter-spacing: -0.025em;
}

.brand-text small {
    color: #66758f;
    font-size: 12px;
    font-weight: 700;
}

.primary-nav {
    gap: 6px;
}

.nav-link,
.nav-contact {
    min-height: 42px;
    color: #29405f;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 800;
}

.nav-link {
    padding: 0 13px;
}

.nav-link::after {
    display: none;
}

.nav-link:hover,
.nav-link.active {
    background: #eaf2ff;
    color: #1d4ed8;
}

.nav-contact {
    background: #ffffff;
    border: 1px solid #cfe0ff;
    color: #1d4ed8;
    box-shadow: none;
    padding-inline: 14px;
}

.nav-contact:hover {
    background: #1d4ed8;
    border-color: #1d4ed8;
    color: #ffffff;
}

.nav-toggle {
    border: 0;
    background: #eaf2ff;
    border-radius: 12px;
    width: 42px;
    height: 38px;
    padding: 8px;
}

.nav-toggle span {
    background: #1d4ed8;
}

.education-section {
    position: relative;
    overflow: hidden;
    background:
        radial-gradient(circle at 12% 10%, rgba(37, 99, 235, 0.10), transparent 26%),
        radial-gradient(circle at 88% 8%, rgba(29, 78, 216, 0.08), transparent 24%),
        linear-gradient(180deg, #f8fbff 0%, #ffffff 58%, #f6f9ff 100%);
}

.education-section::before {
    content: '';
    position: absolute;
    top: 64px;
    right: -58px;
    width: 260px;
    height: 260px;
    border-radius: 50%;
    background: rgba(219, 234, 254, 0.55);
    filter: blur(4px);
    pointer-events: none;
}

.education-timeline {
    position: relative;
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 18px;
    padding-top: 42px;
}

.education-timeline::before {
    content: '';
    position: absolute;
    top: 16px;
    left: 6%;
    right: 6%;
    height: 2px;
    background: linear-gradient(90deg, rgba(29, 78, 216, 0), rgba(29, 78, 216, 0.38), rgba(29, 78, 216, 0));
}

.education-card {
    position: relative;
    min-height: 332px;
    padding: 24px 20px 22px;
    border: 1px solid #dce7f7;
    border-radius: 24px;
    background: rgba(255, 255, 255, 0.94);
    box-shadow: 0 14px 34px rgba(15, 47, 110, 0.07);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.education-card:hover {
    transform: translateY(-4px);
    border-color: #bcd3f5;
    box-shadow: 0 20px 46px rgba(29, 78, 216, 0.12);
}

.education-card::before {
    content: '';
    position: absolute;
    top: -36px;
    left: 50%;
    width: 18px;
    height: 18px;
    border-radius: 999px;
    background: #1d4ed8;
    border: 5px solid #eaf2ff;
    box-shadow: 0 0 0 2px rgba(29, 78, 216, 0.22);
    transform: translateX(-50%);
}

.timeline-year {
    min-width: 76px;
    height: 36px;
    padding: 0 16px;
    border-radius: 999px;
    background: #eaf2ff;
    color: #1d4ed8;
    font-family: var(--font-number);
    font-weight: 900;
    font-size: 15px;
}

.education-icon {
    width: 58px;
    height: 58px;
    margin: 14px 0 12px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(180deg, #eff6ff, #dbeafe);
    color: #1d4ed8;
    font-size: 23px;
}

.education-card h3 {
    margin: 0;
    color: #08265d;
    font-size: 18px;
    line-height: 1.32;
    letter-spacing: -0.025em;
}

.education-school {
    margin-top: 13px;
    color: #314868;
    font-size: 14px;
    font-weight: 700;
    line-height: 1.55;
}

.education-school i {
    color: #1d4ed8;
    margin-right: 4px;
}

.education-focus {
    margin-top: 12px;
    padding-top: 13px;
    border-top: 1px solid #e6edf7;
    color: #5a6d86;
    font-size: 14px;
    line-height: 1.58;
}

@media (max-width: 1180px) {
    .education-timeline {
        grid-template-columns: repeat(3, minmax(0, 1fr));
        padding-top: 0;
    }
    .education-timeline::before,
    .education-card::before {
        display: none;
    }
}

@media (max-width: 820px) {
    .education-timeline {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 620px) {
    .education-timeline {
        grid-template-columns: 1fr;
    }
    .education-card {
        min-height: auto;
        align-items: flex-start;
        text-align: left;
    }
    .education-icon {
        margin-left: 0;
    }
}

/* =========================================================
   v5. Header đồng bộ y chang phong cách hệ thống điểm
   - Nền xanh gradient
   - Chữ trắng
   - Logo học thuật trên nền kính mờ
   - Menu active/hover nền trắng trong suốt
   ========================================================= */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    min-height: 76px;
    background: linear-gradient(120deg, #073f9e, #0b5bd3);
    color: #ffffff;
    border-bottom: 0;
    box-shadow: 0 10px 28px rgba(2, 6, 23, 0.18);
    backdrop-filter: none;
}

.site-header.is-scrolled {
    background: linear-gradient(120deg, #073f9e, #0b5bd3);
    box-shadow: 0 12px 32px rgba(2, 6, 23, 0.22);
}

.header-inner {
    min-height: 76px;
}

.brand {
    color: #ffffff;
}

.brand:hover {
    color: #ffffff;
}

.brand-logo-wrap.brand-logo-academic {
    width: 46px;
    height: 46px;
    flex: 0 0 46px;
    border-radius: 14px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.14);
    border: 1px solid rgba(255, 255, 255, 0.22);
    color: #ffffff;
    box-shadow: none;
    overflow: hidden;
}

.brand-logo-wrap.brand-logo-academic::after {
    display: none;
}

.brand-logo-wrap.brand-logo-academic i {
    font-size: 22px;
    line-height: 1;
    color: #ffffff;
    filter: none;
}

.brand-text strong {
    color: #ffffff;
    font-family: var(--font-number);
    font-size: 20px;
    font-weight: 900;
    line-height: 1.15;
    letter-spacing: -0.03em;
}

.brand-text small {
    display: block;
    margin-top: 2px;
    color: rgba(255, 255, 255, 0.80);
    font-size: 12.5px;
    font-weight: 700;
    white-space: nowrap;
}

.primary-nav {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 6px;
    flex: 1;
}

.nav-link,
.nav-contact {
    min-height: 42px;
    padding: 10px 12px;
    border-radius: 14px;
    color: rgba(255, 255, 255, 0.92);
    background: transparent;
    border: 0;
    box-shadow: none;
    font-size: 14px;
    font-weight: 800;
    line-height: 1;
    white-space: nowrap;
}

.nav-link::after {
    display: none;
}

.nav-link:hover,
.nav-link.active,
.nav-contact:hover {
    background: rgba(255, 255, 255, 0.14);
    color: #ffffff;
}

.nav-contact {
    margin-left: 4px;
    border: 1px solid rgba(255, 255, 255, 0.26);
    padding-inline: 14px;
}

.nav-contact i {
    color: inherit;
}

.nav-toggle {
    width: 44px;
    height: 40px;
    border: 1px solid rgba(255, 255, 255, 0.22);
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.14);
}

.nav-toggle span {
    background: #ffffff;
}

@media (max-width: 860px) {
    .site-header {
        min-height: 68px;
    }

    .header-inner {
        min-height: 68px;
    }

    .brand-logo-wrap.brand-logo-academic {
        width: 42px;
        height: 42px;
        flex-basis: 42px;
        border-radius: 13px;
    }

    .brand-logo-wrap.brand-logo-academic i {
        font-size: 20px;
    }

    .brand-text strong {
        font-size: 17px;
    }

    .brand-text small {
        font-size: 11.5px;
    }

    .primary-nav {
        display: none;
        position: absolute;
        left: 12px;
        right: 12px;
        top: 72px;
        z-index: 110;
        flex-direction: column;
        align-items: stretch;
        gap: 6px;
        padding: 10px;
        border-radius: 18px;
        background: #0b4fbd;
        box-shadow: 0 16px 42px rgba(15, 23, 42, 0.20);
    }

    .primary-nav.open {
        display: flex;
    }

    .primary-nav .nav-link,
    .primary-nav .nav-contact {
        justify-content: flex-start;
        width: 100%;
        min-height: 44px;
        color: rgba(255, 255, 255, 0.94);
        border-radius: 12px;
        padding: 12px 14px;
    }

    .primary-nav .nav-link:hover,
    .primary-nav .nav-link.active,
    .primary-nav .nav-contact:hover {
        background: rgba(255, 255, 255, 0.14);
        color: #ffffff;
    }
}

@media (max-width: 480px) {
    .brand-text small {
        white-space: normal;
    }
}