/* ==========================================================================
   Portfolio - Yacine Berkani | ML Engineer
   Stylesheet moderne avec support dark/light mode
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Variables CSS & Thèmes
   -------------------------------------------------------------------------- */
:root {
    /* Light theme (par défaut) */
    --bg-primary: #fafbfc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f3f4f6;
    --bg-card: #ffffff;
    --bg-overlay: rgba(255, 255, 255, 0.8);

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;

    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-tertiary: #ec4899;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #ec4899 100%);
    --accent-glow: rgba(99, 102, 241, 0.4);

    --border-color: rgba(15, 23, 42, 0.08);
    --border-hover: rgba(99, 102, 241, 0.3);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);

    /* Typographie */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);

    /* Layout */
    --max-width: 1280px;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
}

[data-theme="dark"] {
    --bg-primary: #0a0e1a;
    --bg-secondary: #0f172a;
    --bg-tertiary: #1e293b;
    --bg-card: #111827;
    --bg-overlay: rgba(10, 14, 26, 0.8);

    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #64748b;

    --accent-primary: #818cf8;
    --accent-secondary: #a78bfa;
    --accent-tertiary: #f472b6;
    --accent-gradient: linear-gradient(135deg, #818cf8 0%, #a78bfa 50%, #f472b6 100%);
    --accent-glow: rgba(129, 140, 248, 0.4);

    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(129, 140, 248, 0.4);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 60px rgba(129, 140, 248, 0.2);
}

/* --------------------------------------------------------------------------
   2. Reset & Base
   -------------------------------------------------------------------------- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    overflow-x: hidden;
    transition: background 0.4s ease, color 0.4s ease;
}

::selection {
    background: var(--accent-primary);
    color: #fff;
}

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

a {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition-fast);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* Scrollbar */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb { background: var(--accent-primary); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-secondary); }

/* --------------------------------------------------------------------------
   3. Utilitaires communs
   -------------------------------------------------------------------------- */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 6rem 0;
    position: relative;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 4rem;
}

.section-tag {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    padding: 0.5rem 1rem;
    border-radius: 50px;
    margin-bottom: 1rem;
    font-weight: 500;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

.highlight {
    color: var(--accent-primary);
    font-weight: 600;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.9rem 1.75rem;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--accent-gradient);
    color: #fff;
    box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px var(--accent-glow);
}

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

.btn-secondary:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    transform: translateY(-3px);
}

.btn-full {
    width: 100%;
}

.btn i { transition: transform var(--transition-base); }
.btn:hover i.fa-arrow-right { transform: translateX(4px); }
.btn:hover i.fa-paper-plane { transform: translateX(4px) translateY(-4px); }

/* --------------------------------------------------------------------------
   4. Preloader
   -------------------------------------------------------------------------- */
.preloader {
    position: fixed;
    inset: 0;
    background: var(--bg-primary);
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.preloader.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader {
    position: relative;
    width: 100px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.loader-circle {
    position: absolute;
    inset: 0;
    border: 3px solid var(--border-color);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loader-text {
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 1.5rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* --------------------------------------------------------------------------
   5. Custom Cursor (desktop uniquement)
   -------------------------------------------------------------------------- */
.cursor, .cursor-follower {
    position: fixed;
    pointer-events: none;
    z-index: 9998;
    mix-blend-mode: difference;
    transition: transform 0.1s ease;
}

.cursor {
    width: 8px;
    height: 8px;
    background: var(--accent-primary);
    border-radius: 50%;
}

.cursor-follower {
    width: 30px;
    height: 30px;
    border: 2px solid var(--accent-primary);
    border-radius: 50%;
    transition: transform 0.3s ease;
}

@media (max-width: 1024px) {
    .cursor, .cursor-follower { display: none; }
    body { cursor: auto; }
}

/* --------------------------------------------------------------------------
   6. Scroll progress bar
   -------------------------------------------------------------------------- */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 3px;
    background: var(--accent-gradient);
    z-index: 9997;
    transition: width 0.1s ease;
}

/* --------------------------------------------------------------------------
   7. Navigation
   -------------------------------------------------------------------------- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    padding: 1.25rem 0;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    padding: 0.75rem 0;
    background: var(--bg-overlay);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 2px;
}

.logo-bracket { color: var(--accent-primary); }
.logo-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    padding: 0.5rem 0;
    transition: color var(--transition-fast);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
}

.theme-toggle:hover {
    background: var(--accent-primary);
    color: #fff;
    transform: rotate(30deg) scale(1.1);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    width: 30px;
    padding: 8px 4px;
}

.hamburger span {
    display: block;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-base);
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}
.hamburger.active span:nth-child(2) {
    opacity: 0;
}
.hamburger.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   8. Hero Section
   -------------------------------------------------------------------------- */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    padding: 8rem 0 4rem;
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
}

.hero-gradient {
    position: absolute;
    top: -50%;
    right: -20%;
    width: 80%;
    height: 100%;
    background: radial-gradient(circle, var(--accent-glow) 0%, transparent 60%);
    filter: blur(100px);
}

.hero-grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(var(--border-color) 1px, transparent 1px),
        linear-gradient(90deg, var(--border-color) 1px, transparent 1px);
    background-size: 60px 60px;
    mask-image: radial-gradient(circle at center, black 20%, transparent 80%);
    -webkit-mask-image: radial-gradient(circle at center, black 20%, transparent 80%);
    opacity: 0.4;
}

.floating-shapes {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.shape {
    position: absolute;
    border-radius: 50%;
    background: var(--accent-gradient);
    opacity: 0.1;
    filter: blur(40px);
    animation: float 20s infinite ease-in-out;
}

.shape-1 { width: 300px; height: 300px; top: 10%; left: 5%; }
.shape-2 { width: 200px; height: 200px; top: 60%; left: 80%; animation-delay: -5s; }
.shape-3 { width: 250px; height: 250px; top: 70%; left: 10%; animation-delay: -10s; }
.shape-4 { width: 180px; height: 180px; top: 20%; right: 10%; animation-delay: -15s; }

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(30px, -50px) scale(1.1); }
    50% { transform: translate(-20px, 40px) scale(0.9); }
    75% { transform: translate(40px, 30px) scale(1.05); }
}

.hero-container {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-greeting {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-sm);
}

.greeting-dot {
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: 50%;
    box-shadow: 0 0 10px #22c55e;
    animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1rem;
}

.hero-name {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.hero-subtitle {
    font-size: clamp(1.25rem, 2.5vw, 1.75rem);
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    min-height: 2.5rem;
}

.typed-text {
    color: var(--accent-primary);
    font-weight: 700;
}

.cursor-typed {
    color: var(--accent-primary);
    animation: blink 1s infinite;
    font-weight: 300;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

.hero-description {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    max-width: 560px;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.hero-social {
    display: flex;
    gap: 1rem;
}

.hero-social a {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 1.1rem;
    transition: all var(--transition-base);
}

.hero-social a:hover {
    background: var(--accent-gradient);
    color: #fff;
    border-color: transparent;
    transform: translateY(-5px);
    box-shadow: 0 10px 20px var(--accent-glow);
}

/* Profile visual */
.hero-visual {
    display: flex;
    align-items: center;
    justify-content: center;
}

.profile-container {
    position: relative;
    width: 400px;
    height: 400px;
    max-width: 100%;
}

.profile-ring {
    position: absolute;
    border-radius: 50%;
    border: 2px dashed var(--accent-primary);
    opacity: 0.3;
}

.ring-1 {
    inset: -20px;
    animation: rotate 20s linear infinite;
}

.ring-2 {
    inset: -40px;
    border-color: var(--accent-tertiary);
    animation: rotate 30s linear infinite reverse;
}

@keyframes rotate {
    to { transform: rotate(360deg); }
}

.profile-image {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    overflow: hidden;
    background: var(--accent-gradient);
    padding: 4px;
    box-shadow: var(--shadow-glow), var(--shadow-lg);
    position: relative;
    z-index: 2;
}

.profile-image img {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    background: var(--bg-card);
}

.profile-badge {
    position: absolute;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    padding: 0.6rem 1rem;
    border-radius: 50px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    font-weight: 600;
    box-shadow: var(--shadow-md);
    z-index: 3;
    animation: float-badge 4s ease-in-out infinite;
}

.profile-badge i {
    color: var(--accent-primary);
}

.badge-ml { top: 5%; right: -5%; animation-delay: 0s; }
.badge-cloud { top: 40%; right: -15%; animation-delay: -1s; }
.badge-code { bottom: 20%; left: -15%; animation-delay: -2s; }
.badge-ai { bottom: 5%; right: 5%; animation-delay: -3s; }

@keyframes float-badge {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.75rem;
    color: var(--text-tertiary);
    font-family: var(--font-mono);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.scroll-line {
    width: 2px;
    height: 40px;
    background: linear-gradient(to bottom, var(--accent-primary), transparent);
    position: relative;
    overflow: hidden;
}

.scroll-line::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 50%;
    background: var(--text-primary);
    animation: scroll-move 2s ease-in-out infinite;
}

@keyframes scroll-move {
    0% { transform: translateY(-100%); }
    100% { transform: translateY(200%); }
}

/* --------------------------------------------------------------------------
   9. About Section
   -------------------------------------------------------------------------- */
.about-grid {
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 4rem;
    align-items: start;
}

.about-paragraph {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 1.25rem;
    line-height: 1.8;
}

.about-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.info-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.info-item i {
    color: var(--accent-primary);
    font-size: 1.25rem;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
}

.info-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.info-value {
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text-primary);
}

/* Stats */
.about-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem 1.5rem;
    text-align: center;
    position: relative;
    overflow: hidden;
    transition: all var(--transition-base);
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--accent-gradient);
    transform: translateY(-100%);
    transition: transform var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--border-hover);
}

.stat-card:hover::before {
    transform: translateY(0);
}

.stat-number {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.stat-plus {
    display: inline-block;
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent-primary);
    vertical-align: top;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
    font-weight: 500;
}

/* --------------------------------------------------------------------------
   10. Skills Section
   -------------------------------------------------------------------------- */
.skills {
    background: var(--bg-secondary);
    position: relative;
}

.skills::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent-primary), transparent);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.skill-category {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.skill-category::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--accent-gradient);
    opacity: 0;
    transition: opacity var(--transition-base);
    z-index: 0;
}

.skill-category:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border-color: var(--border-hover);
}

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

.skill-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    background: var(--accent-gradient);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1.25rem;
    box-shadow: 0 4px 15px var(--accent-glow);
}

.skill-category h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.skill-tag {
    padding: 0.4rem 0.9rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.skill-tag small {
    font-size: 0.7rem;
    color: var(--accent-primary);
    margin-left: 2px;
}

.skill-tag:hover {
    background: var(--accent-primary);
    color: #fff;
    border-color: var(--accent-primary);
    transform: translateY(-2px);
}

.skill-tag:hover small { color: rgba(255, 255, 255, 0.8); }

/* --------------------------------------------------------------------------
   11. Experience Timeline
   -------------------------------------------------------------------------- */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 10px;
    width: 2px;
    background: linear-gradient(to bottom,
        var(--accent-primary) 0%,
        var(--accent-secondary) 50%,
        transparent 100%);
}

.timeline-item {
    position: relative;
    padding-bottom: 3rem;
}

.timeline-item:last-child { padding-bottom: 0; }

.timeline-dot {
    position: absolute;
    left: -2rem;
    top: 0.5rem;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--bg-primary);
    border: 3px solid var(--accent-primary);
    box-shadow: 0 0 0 4px var(--bg-primary), 0 0 20px var(--accent-glow);
    z-index: 1;
}

.timeline-content {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    transition: all var(--transition-base);
    position: relative;
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: -10px;
    top: 1rem;
    width: 0;
    height: 0;
    border: 10px solid transparent;
    border-right-color: var(--bg-card);
    filter: drop-shadow(-1px 0 0 var(--border-color));
}

.timeline-content:hover {
    transform: translateX(8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--border-hover);
}

.timeline-date {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    padding: 0.3rem 0.8rem;
    border-radius: 50px;
    margin-bottom: 0.75rem;
    font-weight: 500;
}

.timeline-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.timeline-company {
    font-size: 1rem;
    font-weight: 500;
    color: var(--accent-primary);
    margin-bottom: 0.75rem;
}

.timeline-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 1rem;
}

.timeline-results {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.result-chip {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.35rem 0.8rem;
    background: rgba(34, 197, 94, 0.1);
    color: #16a34a;
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 600;
}

[data-theme="dark"] .result-chip {
    background: rgba(34, 197, 94, 0.15);
    color: #4ade80;
}

/* Education */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
    max-width: 900px;
    margin: 0 auto;
}

.education-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    text-align: center;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.education-card:hover {
    transform: translateY(-5px);
    border-color: var(--border-hover);
    box-shadow: var(--shadow-lg);
}

.education-year {
    font-family: var(--font-mono);
    font-size: 2rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.education-card h4 {
    font-size: 1.05rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.education-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* --------------------------------------------------------------------------
   12. Projects Section
   -------------------------------------------------------------------------- */
.projects {
    background: var(--bg-secondary);
}

.project-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
    margin-bottom: 3rem;
}

.filter-btn {
    padding: 0.6rem 1.4rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.875rem;
    transition: all var(--transition-base);
}

.filter-btn:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.filter-btn.active {
    background: var(--accent-gradient);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 4px 15px var(--accent-glow);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.project-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

.project-card.hidden {
    display: none;
}

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

.project-card:hover {
    transform: translateY(-8px);
    border-color: var(--border-hover);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.project-card:hover::before {
    transform: scaleX(1);
}

.project-icon {
    width: 55px;
    height: 55px;
    border-radius: var(--radius-md);
    background: rgba(99, 102, 241, 0.1);
    color: var(--accent-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1.25rem;
    transition: all var(--transition-base);
}

.project-card:hover .project-icon {
    background: var(--accent-gradient);
    color: #fff;
    transform: rotate(-5deg) scale(1.1);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.75rem;
    gap: 0.75rem;
}

.project-title {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
    flex: 1;
}

.project-category {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    text-transform: uppercase;
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    padding: 0.25rem 0.6rem;
    border-radius: 50px;
    white-space: nowrap;
    letter-spacing: 0.5px;
}

.project-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 1.25rem;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 1.25rem;
}

.project-tag {
    padding: 0.25rem 0.7rem;
    background: var(--bg-tertiary);
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.project-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.project-date {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--accent-primary);
    font-size: 0.85rem;
    font-weight: 600;
    transition: all var(--transition-fast);
}

.project-link:hover {
    gap: 0.7rem;
    color: var(--accent-secondary);
}

.projects-cta {
    text-align: center;
    margin-top: 3rem;
}

.project-video-wrapper {
    width: 100%;
    border-radius: var(--radius-md);
    overflow: hidden;
    margin-bottom: 1.25rem;
    background: #000;
    aspect-ratio: 16 / 9;
    border: 1px solid var(--border-color);
}

.project-video-wrapper video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

/* POC badge (no public GitHub link) */
.project-poc-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text-tertiary);
    font-family: var(--font-mono);
    letter-spacing: 0.3px;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --------------------------------------------------------------------------
   13. Contact Section
   -------------------------------------------------------------------------- */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 4rem;
    align-items: start;
}

.contact-info h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.contact-info p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 2rem;
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.contact-method {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.contact-method:hover {
    transform: translateX(8px);
    border-color: var(--border-hover);
    box-shadow: var(--shadow-md);
}

.method-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
    background: var(--accent-gradient);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    flex-shrink: 0;
    box-shadow: 0 4px 12px var(--accent-glow);
}

.method-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 2px;
}

.method-value {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
    word-break: break-all;
}

/* Contact Form */
.contact-form {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    box-shadow: var(--shadow-md);
}

.form-group {
    position: relative;
    margin-bottom: 2rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 0;
    font-size: 1rem;
    font-family: inherit;
    color: var(--text-primary);
    background: transparent;
    border: none;
    border-bottom: 2px solid var(--border-color);
    outline: none;
    transition: border-color var(--transition-base);
    resize: vertical;
}

.form-group label {
    position: absolute;
    top: 0.75rem;
    left: 0;
    color: var(--text-tertiary);
    font-size: 1rem;
    pointer-events: none;
    transition: all var(--transition-base);
}

.form-group input:focus ~ label,
.form-group input:valid ~ label,
.form-group textarea:focus ~ label,
.form-group textarea:valid ~ label {
    top: -1rem;
    font-size: 0.75rem;
    color: var(--accent-primary);
    font-weight: 500;
}

.form-line {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    transition: width var(--transition-base);
}

.form-group input:focus ~ .form-line,
.form-group textarea:focus ~ .form-line {
    width: 100%;
}

.form-status {
    margin-top: 1rem;
    padding: 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    text-align: center;
    display: none;
}

.form-status.success {
    display: block;
    background: rgba(34, 197, 94, 0.1);
    color: #16a34a;
    border: 1px solid rgba(34, 197, 94, 0.3);
}

.form-status.error {
    display: block;
    background: rgba(239, 68, 68, 0.1);
    color: #dc2626;
    border: 1px solid rgba(239, 68, 68, 0.3);
}

/* --------------------------------------------------------------------------
   14. Footer
   -------------------------------------------------------------------------- */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 4rem 0 2rem;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-brand p {
    color: var(--text-secondary);
    margin-top: 1rem;
    max-width: 400px;
    line-height: 1.7;
}

.footer h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 1.25rem;
    color: var(--text-primary);
}

.footer-links ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.9rem;
    transition: all var(--transition-fast);
}

.footer-links a:hover {
    color: var(--accent-primary);
    padding-left: 4px;
}

.social-links {
    display: flex;
    gap: 0.75rem;
}

.social-links a {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    transition: all var(--transition-base);
}

.social-links a:hover {
    background: var(--accent-gradient);
    color: #fff;
    border-color: transparent;
    transform: translateY(-4px);
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

/* --------------------------------------------------------------------------
   15. Back to top
   -------------------------------------------------------------------------- */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: var(--accent-gradient);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    box-shadow: 0 4px 20px var(--accent-glow);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition-base);
    z-index: 90;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px var(--accent-glow);
}

/* --------------------------------------------------------------------------
   16. Responsive
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }

    .hero-content { max-width: 700px; margin: 0 auto; }
    .hero-description { margin-left: auto; margin-right: auto; }
    .hero-buttons { justify-content: center; }
    .hero-social { justify-content: center; }

    .profile-container { width: 320px; height: 320px; }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

    .contact-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

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

@media (max-width: 768px) {
    .section { padding: 4rem 0; }

    .nav-menu {
        position: fixed;
        top: 70px;
        right: -100%;
        width: 280px;
        height: calc(100vh - 70px);
        background: var(--bg-card);
        border-left: 1px solid var(--border-color);
        flex-direction: column;
        padding: 2rem;
        transition: right var(--transition-base);
        box-shadow: var(--shadow-lg);
    }

    .nav-menu.active {
        right: 0;
    }

    .hamburger { display: flex; }

    .hero-title { font-size: 2.5rem; }
    .hero-subtitle { font-size: 1.25rem; }

    .profile-container { width: 280px; height: 280px; }
    .profile-badge { font-size: 0.75rem; padding: 0.4rem 0.8rem; }

    .about-info { grid-template-columns: 1fr; }
    .about-stats { grid-template-columns: 1fr 1fr; gap: 1rem; }

    .stat-number { font-size: 2.25rem; }

    .timeline { padding-left: 1.5rem; }
    .timeline-dot { left: -1.5rem; width: 18px; height: 18px; }

    .contact-form { padding: 1.75rem; }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .social-links { justify-content: center; }
    .footer-bottom { flex-direction: column; text-align: center; }

    .back-to-top { bottom: 1.5rem; right: 1.5rem; width: 45px; height: 45px; }
}

@media (max-width: 480px) {
    .container { padding: 0 1rem; }

    .hero { padding: 7rem 0 3rem; }
    .hero-title { font-size: 2rem; }
    .hero-buttons .btn { width: 100%; }

    .profile-container { width: 240px; height: 240px; }

    .section-title { font-size: 1.75rem; }

    .skill-category { padding: 1.5rem; }
    .project-card { padding: 1.5rem; }

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

/* --------------------------------------------------------------------------
   17. Print styles
   -------------------------------------------------------------------------- */
@media print {
    .navbar, .hero-social, .scroll-indicator, .back-to-top,
    .preloader, .cursor, .cursor-follower, .scroll-progress { display: none !important; }
}