:root {
    /* Palette Tối & Hiện đại - Dark Mode */
    --primary-color: #0a0e27;
    /* Đậm, mạnh mẽ */
    --secondary-color: #1e293b;
    --accent-color: #6366f1;
    /* Indigo 500 - Sáng, nổi bật */
    --accent-hover: #818cf8;
    --accent-light: #a5b4fc;
    --text-primary: #f8fafc;
    /* Sáng trên nền tối */
    --text-secondary: #cbd5e1;
    --text-light: #94a3b8;
    --bg-primary: #0f172a;
    /* Nền tối chính */
    --bg-secondary: #1e293b;
    /* Nền tối phụ */
    --bg-light: #334155;
    /* Nền tối nhẹ */
    --bg-card: #1e293b;
    /* Nền card */
    --bg-dark: #0a0e27;
    --border-color: #334155;
    --border-light: #475569;

    /* Hiệu ứng mạnh mẽ hơn */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 8px 16px rgba(0, 0, 0, 0.12), 0 4px 8px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.15), 0 8px 16px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 32px 64px rgba(0, 0, 0, 0.2), 0 16px 32px rgba(0, 0, 0, 0.15);
    --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.25);
    --shadow-glow-strong: 0 0 50px rgba(99, 102, 241, 0.35);

    --transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);

    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #06b6d4 100%);
    --gradient-text: linear-gradient(135deg, #f8fafc 0%, #cbd5e1 30%, #6366f1 100%);
    --gradient-accent: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-dark: linear-gradient(135deg, #0a0e27 0%, #1e293b 100%);

    /* Hình chữ nhật và vuông - mạnh mẽ */
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.7;
    color: var(--text-secondary);
    background-color: var(--bg-primary);
    background-image:
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.05) 0%, transparent 50%);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

h1,
h2,
h3,
h4,
h5 {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 800;
    /* Cực đậm để mạnh mẽ */
    color: var(--primary-color);
    letter-spacing: -0.04em;
    line-height: 1.1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(30px);
    padding: 20px 0;
    z-index: 1000;
    transition: var(--transition);
    border-bottom: 2px solid rgba(51, 65, 85, 0.8);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.navbar.scrolled {
    background: rgba(15, 23, 42, 0.98);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4), 0 0 0 1px rgba(99, 102, 241, 0.2);
    border-bottom: 2px solid rgba(99, 102, 241, 0.3);
    padding: 16px 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 1px;
    text-decoration: none;
    transition: var(--transition);
    position: relative;
}

.logo::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 3px;
    background: var(--gradient-primary);
    transition: var(--transition);
    border-radius: 2px;
}

.logo:hover::after {
    width: 100%;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
    position: relative;
    padding: 4px 0;
}

.nav-links a:hover {
    color: var(--accent-light);
}

.nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 3px;
    bottom: 0;
    left: 0;
    background: var(--gradient-primary);
    transition: var(--transition);
    border-radius: 2px;
}


.nav-links a:hover::after {
    width: 100%;
}

.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-primary);
}

/* Layout Switcher Dropdown */
.layout-switcher {
    position: relative;
}

.layout-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px !important;
    background: rgba(99, 102, 241, 0.1);
    border: 2px solid rgba(99, 102, 241, 0.3);
    border-radius: 8px;
}

.layout-btn:hover {
    background: rgba(99, 102, 241, 0.2);
    border-color: var(--accent-color);
}

.layout-dropdown {
    position: absolute;
    top: calc(100% + 12px);
    right: 0;
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    min-width: 200px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--transition);
    z-index: 1000;
}

.layout-switcher:hover .layout-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.layout-dropdown a {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
    border-bottom: 1px solid var(--border-color);
}

.layout-dropdown a:last-child {
    border-bottom: none;
}

.layout-dropdown a:hover {
    background: rgba(99, 102, 241, 0.1);
    color: var(--accent-light);
    padding-left: 24px;
}

.layout-dropdown a.active {
    background: rgba(99, 102, 241, 0.15);
    color: var(--accent-color);
    font-weight: 600;
}

.layout-dropdown a i {
    width: 16px;
    text-align: center;
}

/* Hero Section Upgrade */
.hero {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0a0e27 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 900px;
    height: 900px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.12) 0%, rgba(139, 92, 246, 0.08) 50%, transparent 70%);
    border-radius: 50%;
    z-index: 0;
    animation: float 20s ease-in-out infinite;
    filter: blur(40px);
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -5%;
    width: 700px;
    height: 700px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.1) 0%, rgba(99, 102, 241, 0.06) 50%, transparent 70%);
    border-radius: 50%;
    z-index: 0;
    animation: float 25s ease-in-out infinite reverse;
    filter: blur(50px);
}

@keyframes float {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    50% {
        transform: translate(30px, -30px) scale(1.1);
    }
}

.hero-text h1 {
    font-size: 5rem;
    line-height: 1;
    margin-bottom: 28px;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 900;
    letter-spacing: -0.05em;
    position: relative;
    text-shadow: 0 0 80px rgba(99, 102, 241, 0.3);
    color: var(--text-primary);
}

.hero-text h1::before {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 0;
    width: 140px;
    height: 6px;
    background: var(--gradient-primary);
    border-radius: 4px;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
    animation: slideIn 1s ease-out;
}

@keyframes slideIn {
    from {
        width: 0;
        opacity: 0;
    }

    to {
        width: 140px;
        opacity: 1;
    }
}

.greeting {
    color: var(--accent-color);
    font-weight: 800;
    letter-spacing: 3px;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(139, 92, 246, 0.12) 100%);
    display: inline-block;
    padding: 10px 20px;
    border-radius: 50px;
    font-size: 0.85rem;
    margin-bottom: 24px;
    border: 2px solid rgba(99, 102, 241, 0.3);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.8);
    text-transform: uppercase;
    position: relative;
    overflow: hidden;
}

.greeting::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0.1;
    transition: var(--transition);
}

.greeting:hover::before {
    left: 0;
}

.hero-content {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    min-height: 100vh;
    padding-top: 80px;
}

.hero-text {
    max-width: 600px;
}

.subtitle {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: 28px;
    font-weight: 700;
    letter-spacing: -0.03em;
    position: relative;
    display: inline-block;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle::before {
    content: '▸';
    color: var(--accent-color);
    margin-right: 14px;
    font-size: 1.4rem;
    display: inline-block;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
        opacity: 1;
    }

    50% {
        transform: scale(1.2);
        opacity: 0.8;
    }
}

.hero-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
    line-height: 1.8;
    font-weight: 500;
    letter-spacing: -0.01em;
}

.hero-description strong {
    color: var(--accent-light);
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.cta-buttons {
    display: flex;
    gap: 16px;
}

.btn {
    display: inline-block;
    padding: 12px 32px;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.3), var(--shadow-glow);
    font-weight: 700;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    font-size: 0.95rem;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #8b5cf6 0%, #06b6d4 100%);
    transition: var(--transition);
    z-index: 0;
}

.btn-primary::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: var(--transition);
}

.btn-primary span {
    position: relative;
    z-index: 1;
    display: inline-block;
    transition: var(--transition);
}

.btn-primary:hover {
    box-shadow: 0 12px 32px rgba(99, 102, 241, 0.4), var(--shadow-glow-strong);
    transform: translateY(-4px) scale(1.02);
}

.btn-primary:hover::before {
    left: 0;
}

.btn-primary:hover::after {
    width: 300px;
    height: 300px;
}

.btn-primary:hover span {
    transform: scale(1.05);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--border-color);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    background: var(--primary-color);
    color: white;
}

.hero-image {
    display: flex;
    justify-content: center;
    position: relative;
}

.image-wrapper {
    position: relative;
    width: 380px;
    height: 480px;
    z-index: 2;
}

.image-wrapper::before {
    content: '';
    position: absolute;
    top: -25px;
    right: -25px;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 24px;
    opacity: 0.2;
    z-index: -1;
    transform: rotate(4deg);
    box-shadow: 0 20px 60px rgba(99, 102, 241, 0.3);
    animation: rotate 20s linear infinite;
}

.image-wrapper::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: -20px;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(139, 92, 246, 0.1) 50%, rgba(6, 182, 212, 0.1) 100%);
    border-radius: 24px;
    z-index: -2;
    transform: rotate(-3deg);
    box-shadow: 0 20px 60px rgba(6, 182, 212, 0.2);
    animation: rotate 25s linear infinite reverse;
}

@keyframes rotate {
    from {
        transform: rotate(4deg);
    }

    to {
        transform: rotate(364deg);
    }
}

.image-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 24px;
    box-shadow: 0 25px 80px rgba(0, 0, 0, 0.2), 0 0 0 2px rgba(255, 255, 255, 0.8), var(--shadow-glow);
    transition: var(--transition);
    position: relative;
    z-index: 1;
    filter: brightness(1.02) contrast(1.05);
}

.image-wrapper:hover img {
    transform: scale(1.03);
    box-shadow: 0 30px 100px rgba(0, 0, 0, 0.25), 0 0 0 2px rgba(255, 255, 255, 0.9), var(--shadow-glow-strong);
    filter: brightness(1.05) contrast(1.08);
}

.image-border {
    position: absolute;
    top: 15px;
    right: 15px;
    width: 100%;
    height: 100%;
    border: 3px solid var(--accent-color);
    border-radius: 20px;
    opacity: 0.3;
    z-index: 0;
    transform: rotate(1deg);
    transition: var(--transition);
}

.image-wrapper:hover .image-border {
    opacity: 0.5;
    transform: rotate(2deg) scale(1.02);
}

/* Timeline Upgrade */
.timeline-item {
    padding-left: 30px;
    border-left: 2px solid var(--border-color);
    margin-left: 10px;
}

.timeline-date {
    color: var(--accent-color);
    font-weight: 700;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.timeline-content h3 {
    color: var(--text-primary);
    font-size: 1.6rem;
}

.project-item h5 {
    color: var(--secondary-color);
    font-weight: 600;
}

.project-item h5 i {
    color: var(--accent-color);
    margin-right: 8px;
}

/* Sections */
.section {
    padding: 120px 0;
}

.bg-light {
    background-color: var(--bg-secondary);
    background-image:
        radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 90% 80%, rgba(139, 92, 246, 0.03) 0%, transparent 50%);
}

.section-title {
    font-size: 3.5rem;
    text-align: center;
    margin-bottom: 32px;
    position: relative;
    font-weight: 900;
    letter-spacing: -0.04em;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: var(--text-primary);
}

.section-title::before {
    content: '';
    position: absolute;
    top: -16px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 6px;
    background: var(--gradient-primary);
    border-radius: 4px;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 120px;
    height: 4px;
    background: var(--gradient-primary);
    border-radius: 2px;
    opacity: 0.6;
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}

.section-desc {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 60px;
}

/* About Section */
.about-content {
    max-width: 1000px;
    margin: 0 auto;
}

.about-text {
    margin-bottom: 60px;
}

.about-text .lead {
    font-size: 1.4rem;
    color: var(--text-primary);
    margin-bottom: 32px;
    line-height: 1.8;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.about-text .lead strong {
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.about-text p {
    color: var(--text-secondary);
}

.about-text p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 16px;
}

.about-highlights {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-top: 60px;
}

.highlight-item {
    text-align: center;
    padding: 48px 32px;
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.highlight-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

.highlight-item:hover::before {
    transform: scaleX(1);
}

.highlight-item:hover {
    transform: translateY(-16px) scale(1.02);
    box-shadow: 0 20px 48px rgba(0, 0, 0, 0.15), var(--shadow-glow);
    border-color: rgba(99, 102, 241, 0.4);
}

.highlight-item i {
    transition: var(--transition);
}

.highlight-item:hover i {
    transform: scale(1.2) rotate(5deg);
    filter: drop-shadow(0 4px 8px rgba(99, 102, 241, 0.4));
}

.highlight-item i {
    font-size: 2.5rem;
    color: var(--accent-color);
    margin-bottom: 20px;
}

.highlight-item h3 {
    font-size: 2rem;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.highlight-item p {
    color: var(--text-secondary);
}

.highlight-item p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Timeline */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding-left: 40px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--accent-color), rgba(74, 144, 226, 0.15));
}

.timeline-item {
    position: relative;
    margin-bottom: 60px;
    padding-left: 60px;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 0;
    width: 14px;
    height: 14px;
    background: var(--accent-color);
    border-radius: 50%;
    border: 3px solid white;
    box-shadow: 0 0 0 3px var(--accent-color);
}

.timeline-date {
    position: absolute;
    left: -200px;
    top: 0;
    font-weight: 600;
    color: var(--accent-color);
    font-size: 0.9rem;
    white-space: nowrap;
}

.timeline-content {
    background: var(--bg-card);
    padding: 36px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

/* Animated border cho timeline item hiện tại */
.timeline-item.current .timeline-content {
    border: 2px solid var(--accent-color);
    animation: borderPulse 2s ease-in-out infinite;
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.3), var(--shadow-glow);
}

@keyframes borderPulse {

    0%,
    100% {
        border-color: var(--accent-color);
        box-shadow: 0 0 20px rgba(99, 102, 241, 0.3), var(--shadow-glow);
    }

    50% {
        border-color: var(--accent-light);
        box-shadow: 0 0 30px rgba(99, 102, 241, 0.5), var(--shadow-glow-strong);
    }
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 4px;
    height: 100%;
    background: var(--gradient-primary);
    transform: scaleY(0);
    transform-origin: top;
    transition: var(--transition);
}

.timeline-content:hover::before {
    transform: scaleY(1);
}

.timeline-content:hover {
    transform: translateX(16px) scale(1.01);
    box-shadow: 0 20px 48px rgba(0, 0, 0, 0.15), var(--shadow-glow);
    border-color: rgba(99, 102, 241, 0.4);
}

.timeline-content h3 {
    font-size: 1.6rem;
    margin-bottom: 10px;
    color: var(--text-primary);
    font-weight: 800;
    letter-spacing: -0.02em;
}

.timeline-content h4 {
    font-size: 1.1rem;
    color: var(--accent-light);
    margin-bottom: 16px;
    font-weight: 500;
}

.timeline-description {
    color: var(--text-secondary);
    margin-bottom: 24px;
    line-height: 1.8;
}

.timeline-content {
    color: var(--text-secondary);
}

.projects {
    display: grid;
    gap: 20px;
    margin-top: 24px;
}

.project-item {
    padding: 24px;
    background: var(--bg-light);
    border-left: 5px solid var(--accent-color);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.project-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 5px;
    height: 100%;
    background: var(--gradient-primary);
    transform: scaleY(0);
    transform-origin: top;
    transition: var(--transition);
}

.project-item:hover::before {
    transform: scaleY(1);
}

.project-item:hover {
    background: var(--bg-card);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4), var(--shadow-glow);
    transform: translateX(8px) scale(1.01);
    border-left-width: 6px;
}

.project-item h5 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.project-item p {
    color: var(--text-secondary);
}

.project-item h5 i {
    color: var(--accent-color);
    font-size: 1rem;
}

.project-item p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Education Section */
.education-timeline {
    max-width: 900px;
    margin: 0 auto;
    display: grid;
    gap: 40px;
}

.education-item {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 40px;
    padding: 40px;
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

/* Animated border cho education item hiện tại */
.education-item.current {
    border: 2px solid var(--accent-color);
    animation: borderPulse 2s ease-in-out infinite;
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.3), var(--shadow-glow);
}

.education-item.current::before {
    background: var(--gradient-primary);
    animation: gradientShift 3s ease-in-out infinite;
}

@keyframes gradientShift {

    0%,
    100% {
        background: var(--gradient-primary);
    }

    50% {
        background: linear-gradient(135deg, #8b5cf6 0%, #6366f1 50%, #06b6d4 100%);
    }
}

.education-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 4px;
    height: 100%;
    background: var(--gradient-primary);
    transform: scaleY(0);
    transform-origin: top;
    transition: var(--transition);
}

.education-item:hover::before {
    transform: scaleY(1);
}

.education-item:hover {
    transform: translateY(-12px) scale(1.01);
    box-shadow: 0 20px 48px rgba(0, 0, 0, 0.15), var(--shadow-glow);
    border-color: rgba(99, 102, 241, 0.4);
}

.education-year {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent-color);
    line-height: 1.6;
}

.education-year span {
    display: block;
    font-size: 0.85rem;
    color: var(--text-light);
    font-weight: 400;
    margin-top: 4px;
}

.education-content h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--text-primary);
    font-weight: 800;
    letter-spacing: -0.02em;
}

.education-content h4 {
    font-size: 1rem;
    color: var(--text-light);
    margin-bottom: 16px;
    font-weight: 500;
}

.education-content p {
    color: var(--text-secondary);
    line-height: 1.8;
}

.education-year {
    color: var(--accent-light);
}

/* Skills Section */
.skills-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    max-width: 1200px;
    margin: 0 auto;
}

.skills-category {
    background: var(--bg-card);
    padding: 36px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.skills-category::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 100px;
    height: 100px;
    background: radial-gradient(circle, rgba(79, 70, 229, 0.05) 0%, transparent 70%);
    border-radius: 50%;
    transform: translate(30px, -30px);
    transition: var(--transition);
}

.skills-category:hover::after {
    transform: translate(20px, -20px) scale(1.5);
}

.skills-category:hover {
    transform: translateY(-16px) scale(1.02);
    box-shadow: 0 20px 48px rgba(0, 0, 0, 0.15), var(--shadow-glow);
    border-color: rgba(99, 102, 241, 0.4);
}

.category-header i {
    transition: var(--transition);
}

.skills-category:hover .category-header i {
    transform: scale(1.3) rotate(10deg);
    filter: drop-shadow(0 4px 12px rgba(99, 102, 241, 0.5));
}

.category-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--border-color);
}

.category-header h3 {
    color: var(--text-primary);
}

.category-header i {
    font-size: 1.8rem;
    color: var(--accent-color);
}

.category-header h3 {
    font-size: 1.4rem;
    margin: 0;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.skills-list {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.skill-tag {
    display: inline-block;
    padding: 10px 18px;
    background: var(--bg-light);
    color: var(--text-primary);
    font-size: 0.9rem;
    font-weight: 600;
    transition: var(--transition);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.skill-tag::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    transition: var(--transition);
    z-index: 0;
}

.skill-tag>* {
    position: relative;
    z-index: 1;
}

.skill-tag:hover {
    color: white;
    transform: translateY(-4px) scale(1.05);
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.4), var(--shadow-glow);
    border-color: var(--accent-color);
}

.skill-tag:hover::before {
    left: 0;
}

/* Gallery Section */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 40px;
}

.gallery-item {
    position: relative;
    height: 320px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    cursor: pointer;
    border: 2px solid var(--border-color);
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.gallery-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition);
    z-index: 1;
    mix-blend-mode: overlay;
}

.gallery-item:hover::before {
    opacity: 0.1;
}

.gallery-item:hover {
    transform: translateY(-16px) scale(1.02);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.2), var(--shadow-glow-strong);
    border-color: rgba(99, 102, 241, 0.4);
}

.gallery-item:hover img {
    transform: scale(1.1);
}

.overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(15, 23, 42, 0.95) 0%, rgba(15, 23, 42, 0.7) 50%, transparent 100%);
    padding: 28px;
    transform: translateY(100%);
    transition: var(--transition);
    z-index: 2;
}

.gallery-item:hover .overlay {
    transform: translateY(0);
}

.overlay h3 {
    color: white;
    font-size: 1.3rem;
    margin: 0;
    font-weight: 700;
    letter-spacing: -0.02em;
}

/* Contact Section */
.contact-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contact-intro {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 48px;
}

.contact-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 32px;
}

.contact-item {
    padding: 36px;
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.contact-item::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

.contact-item:hover::after {
    transform: scaleX(1);
}

.contact-item:hover {
    transform: translateY(-16px) scale(1.02);
    box-shadow: 0 20px 48px rgba(0, 0, 0, 0.15), var(--shadow-glow);
    border-color: rgba(99, 102, 241, 0.4);
}

.contact-item i {
    transition: var(--transition);
}

.contact-item:hover i {
    transform: scale(1.3) rotate(10deg);
    filter: drop-shadow(0 4px 12px rgba(99, 102, 241, 0.5));
}

.contact-item i {
    font-size: 2.5rem;
    color: var(--accent-color);
    margin-bottom: 16px;
}

.contact-item p {
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.contact-link {
    color: var(--accent-light);
}

.contact-link {
    color: var(--accent-color);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition);
}

.contact-link:hover {
    text-decoration: underline;
}

/* Footer */
footer {
    background: linear-gradient(135deg, var(--primary-color) 0%, #1e293b 100%);
    color: white;
    padding: 48px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: var(--gradient-primary);
    opacity: 0.3;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-content p {
    margin: 0;
    color: rgba(255, 255, 255, 0.8);
}

.footer-content span {
    color: white;
    font-weight: 600;
}

.design-credit {
    font-size: 0.9rem;
}

.design-credit i {
    color: #ff6b6b;
    margin: 0 4px;
}

/* Animations */
.reveal {
    opacity: 0;
    transform: translateY(50px) scale(0.95);
    transition: all 1s cubic-bezier(0.4, 0, 0.2, 1);
    filter: blur(4px);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0) scale(1);
    filter: blur(0);
}

/* Smooth scroll indicator */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
    color: var(--text-light);
    font-size: 1.5rem;
    z-index: 10;
    cursor: pointer;
    transition: var(--transition);
}

.scroll-indicator:hover {
    color: var(--accent-color);
    transform: translateX(-50%) translateY(5px);
}

@keyframes bounce {

    0%,
    20%,
    50%,
    80%,
    100% {
        transform: translateX(-50%) translateY(0);
    }

    40% {
        transform: translateX(-50%) translateY(-10px);
    }

    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}

/* Responsive Design */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }

    .hero-text {
        max-width: 100%;
    }

    .hero-text h1 {
        font-size: 3rem;
    }

    .image-wrapper {
        width: 300px;
        height: 400px;
        margin: 0 auto;
    }

    .timeline {
        padding-left: 0;
    }

    .timeline::before {
        display: none;
    }

    .timeline-item {
        padding-left: 0;
    }

    .timeline-item::before {
        display: none;
    }

    .timeline-date {
        position: static;
        margin-bottom: 12px;
        display: block;
    }

    .education-item {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .education-year {
        text-align: left;
    }

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

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: rgba(15, 23, 42, 0.98);
        padding: 20px;
        border-bottom: 1px solid var(--border-color);
        box-shadow: 0 10px 30px rgba(0,0,0,0.5);
        z-index: 1000;
    }

    .nav-links.active li {
        width: 100%;
        text-align: center;
        margin: 10px 0;
    }

    .hamburger {
        display: block;
        cursor: pointer;
        font-size: 1.5rem;
        color: var(--text-primary);
    }

    .hero {
        padding-top: 120px; /* Fix layout overlap */
        align-items: flex-start; /* Align to top to avoid centering issues on small screens */
    }

    .hero-text h1 {
        font-size: 2.5rem;
    }

    .section-title {
        font-size: 2.2rem;
    }

    .section {
        padding: 80px 0;
    }

    .container {
        padding: 0 20px;
    }

    .skills-container {
        grid-template-columns: 1fr;
    }

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

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

@media (max-width: 480px) {
    .hero-text h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1.2rem;
    }

    .cta-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        text-align: center;
    }
}