/* ========================================
   CSS Variables & Theme Configuration
   ======================================== */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --accent-primary: #22c55e;
    --accent-secondary: #16a34a;
    --accent-light: #f0fdf4;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --card-bg: #ffffff;
    --timeline-line: #e2e8f0;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
}

[data-theme="dark"] {
    --bg-primary: #0a0a0a;
    --bg-secondary: #111111;
    --bg-tertiary: #1a1a1a;
    --text-primary: #f9fafb;
    --text-secondary: #9ca3af;
    --text-muted: #6b7280;
    --accent-primary: #4ade80;
    --accent-secondary: #22c55e;
    --accent-light: #052e16;
    --border-color: #262626;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --card-bg: #111111;
    --timeline-line: #262626;
}

/* ========================================
   Base Styles & Reset
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
    min-height: 100vh;
}

a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--accent-secondary);
}

img {
    max-width: 100%;
    height: auto;
}

/* ========================================
   Navigation
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    backdrop-filter: blur(12px);
    background: rgba(255, 255, 255, 0.85);
    border-bottom: 1px solid var(--border-color);
}

[data-theme="dark"] .navbar {
    background: rgba(10, 10, 10, 0.85);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.025em;
}

.nav-logo span {
    color: var(--accent-primary);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 4px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--text-primary);
    background-color: var(--bg-tertiary);
}

.nav-link.active {
    color: var(--accent-primary);
    background-color: var(--accent-light);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.btn-download {
    padding: 8px 16px;
    background-color: var(--accent-primary);
    color: white;
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 0.85rem;
    transition: all 0.2s ease;
}

.btn-download:hover {
    background-color: var(--accent-secondary);
    color: white;
}

.theme-btn {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    transition: all 0.2s ease;
}

.theme-btn:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--accent-primary);
}

.theme-btn .sun-icon {
    display: none;
}

.theme-btn .moon-icon {
    display: block;
}

[data-theme="dark"] .theme-btn .sun-icon {
    display: block;
}

[data-theme="dark"] .theme-btn .moon-icon {
    display: none;
}

/* ========================================
   Main Content
   ======================================== */
.main-content {
    padding-top: 60px;
    min-height: 100vh;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    padding: 100px 0 80px;
    text-align: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    background-color: var(--accent-light);
    color: var(--accent-primary);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: 24px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.hero-title .highlight {
    color: var(--accent-primary);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    flex-wrap: wrap;
}

.hero-link {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s ease;
}

.hero-link:hover {
    color: var(--accent-primary);
}

/* ========================================
   Page Header
   ======================================== */
.page-header {
    padding: 80px 0 60px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 60px;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.page-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ========================================
   Section Styles
   ======================================== */
.section {
    padding: 60px 0;
}

.section-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 24px;
}

/* ========================================
   Timeline Styles
   ======================================== */
.timeline {
    position: relative;
    padding-left: 24px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-color);
}

.timeline-item {
    position: relative;
    padding-bottom: 40px;
}

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

.timeline-marker {
    position: absolute;
    left: -29px;
    top: 4px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--accent-primary);
    border: 2px solid var(--bg-primary);
}

.timeline-content {
    background: var(--card-bg);
    padding: 24px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.timeline-header {
    margin-bottom: 16px;
}

.timeline-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.timeline-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.timeline-company {
    color: var(--accent-primary);
    font-weight: 500;
}

.timeline-list {
    list-style: none;
    padding: 0;
}

.timeline-list li {
    position: relative;
    padding-left: 16px;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

.timeline-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--accent-primary);
}

/* ========================================
   Projects Section
   ======================================== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 24px;
}

.project-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all 0.3s ease;
}

.project-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-primary);
}

.project-video {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    background: #000;
    display: block;
}

.project-video .video-thumbnail {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.project-video-link:hover .video-thumbnail {
    transform: scale(1.02);
}

.project-video .play-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.4);
    transition: background 0.3s ease;
    z-index: 2;
}

.project-video-link:hover .play-overlay {
    background: rgba(0, 0, 0, 0.2);
}

.project-video .play-overlay svg {
    width: 64px;
    height: 64px;
    filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.5));
    transition: transform 0.3s ease;
}

.project-video-link:hover .play-overlay svg {
    transform: scale(1.1);
}

.project-content {
    padding: 20px;
}

.project-content h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.project-content p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
    line-height: 1.6;
}

.project-links {
    display: flex;
    gap: 16px;
}

.project-link {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--accent-primary);
}

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

/* ========================================
   Skills Section
   ======================================== */
.skills-category {
    margin-bottom: 48px;
}

.skills-category:last-child {
    margin-bottom: 0;
}

.skills-category-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.skills-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.skill-item {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 100px;
    padding: 8px 16px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: all 0.2s ease;
}

.skill-item:hover {
    background-color: var(--accent-light);
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.management-list {
    list-style: none;
    padding: 0;
}

.management-list li {
    position: relative;
    padding-left: 16px;
    margin-bottom: 12px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.management-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--accent-primary);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    border-top: 1px solid var(--border-color);
    padding: 32px 0;
    text-align: center;
    margin-top: 80px;
}

.footer p {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 16px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
}

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

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 16px;
    }

    .nav-menu {
        display: none;
    }

    .hero {
        padding: 60px 0;
    }

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

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-links {
        flex-direction: column;
        gap: 12px;
    }

    .page-header {
        padding: 60px 0 40px;
    }

    .page-header h1 {
        font-size: 2rem;
    }

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

    .timeline {
        padding-left: 20px;
    }

    .timeline-marker {
        left: -25px;
        width: 10px;
        height: 10px;
    }
}

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

    .section {
        padding: 40px 0;
    }
}