/* ============================================
   charleschen.ai — Dark Techy Professional
   ============================================ */

:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #0f0f18;
    --bg-card: #13131f;
    --bg-card-hover: #1a1a2e;
    --border: #1e1e35;
    --border-hover: #2d2d50;
    --text-primary: #e8e8f0;
    --text-secondary: #8888a8;
    --text-muted: #55556a;
    --accent-1: #6366f1;
    --accent-2: #8b5cf6;
    --accent-3: #06b6d4;
    --gradient: linear-gradient(135deg, var(--accent-1), var(--accent-2), var(--accent-3));
    --gradient-text: linear-gradient(135deg, #818cf8, #a78bfa, #22d3ee);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 48px rgba(0, 0, 0, 0.4);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

/* ---- Navigation ---- */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: border-color var(--transition);
}

.nav.scrolled {
    border-bottom-color: var(--border);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.nav-logo {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.logo-bracket {
    color: var(--accent-1);
    font-weight: 400;
}

.logo-highlight {
    color: var(--accent-3);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition);
    letter-spacing: 0.01em;
}

.nav-links a:hover {
    color: var(--text-primary);
}

.nav-github {
    display: flex;
    align-items: center;
    opacity: 0.6;
    transition: opacity var(--transition);
}

.nav-github:hover {
    opacity: 1;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

/* ---- Hero ---- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    overflow: hidden;
}

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

#hero-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    opacity: 0.4;
}

.hero-content {
    position: relative;
    z-index: 1;
    padding: 120px 0 80px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--accent-1);
    margin-bottom: 32px;
    animation: fadeInUp 0.8s ease;
}

.hero-badge::before {
    content: '';
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: 50%;
    animation: pulse 2s infinite;
}

.hero-title {
    font-size: clamp(2.5rem, 5.5vw, 4.5rem);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 24px;
    animation: fadeInUp 0.8s ease 0.1s both;
}

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

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    line-height: 1.7;
    max-width: 600px;
    margin-bottom: 40px;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 64px;
    animation: fadeInUp 0.8s ease 0.3s both;
}

.hero-stats {
    display: flex;
    align-items: center;
    gap: 32px;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.stat-value {
    display: block;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    font-family: var(--font-mono);
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--border);
}

.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: var(--text-muted);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    animation: fadeInUp 0.8s ease 0.5s both;
}

.scroll-line {
    width: 1px;
    height: 48px;
    background: linear-gradient(to bottom, var(--accent-1), transparent);
    animation: scrollPulse 2s ease infinite;
}

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition);
    cursor: pointer;
    border: none;
    letter-spacing: 0.01em;
}

.btn-primary {
    background: var(--gradient);
    color: #fff;
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(99, 102, 241, 0.4);
}

.btn-outline {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-outline:hover {
    border-color: var(--border-hover);
    background: rgba(255, 255, 255, 0.03);
}

.btn-full {
    width: 100%;
}

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

.section-alt {
    background: var(--bg-secondary);
}

.section-label {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--accent-1);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 16px;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 56px;
}

/* ---- About ---- */
.about-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 64px;
    align-items: start;
}

.about-text h2 {
    font-size: clamp(2rem, 3.5vw, 2.8rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 24px;
    line-height: 1.15;
}

.about-text p {
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-size: 1.05rem;
    line-height: 1.7;
}

.about-highlights {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 32px;
}

.highlight {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    transition: border-color var(--transition);
}

.highlight:hover {
    border-color: var(--border-hover);
}

.highlight-icon {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 8px;
    color: var(--accent-1);
}

.highlight strong {
    display: block;
    font-size: 0.95rem;
    margin-bottom: 2px;
}

.highlight span {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.about-tech {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px;
    position: sticky;
    top: 100px;
}

.about-tech h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 24px;
}

.tech-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.tech-category h4 {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.12em;
    margin-bottom: 10px;
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tech-tags span {
    padding: 6px 12px;
    background: rgba(99, 102, 241, 0.08);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.tech-tags span:hover {
    border-color: var(--accent-1);
    color: var(--text-primary);
    background: rgba(99, 102, 241, 0.12);
}

/* ---- Services ---- */
.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

@media (max-width: 1024px) {
    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.service-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
    transition: all var(--transition);
}

.service-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.service-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    color: var(--accent-1);
    margin-bottom: 24px;
}

.service-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.service-card > p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 20px;
}

.service-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.service-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.88rem;
    color: var(--text-secondary);
}

.service-list li::before {
    content: '';
    flex-shrink: 0;
    width: 6px;
    height: 6px;
    background: var(--accent-3);
    border-radius: 50%;
}

/* ---- Portfolio ---- */
.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.portfolio-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
    transition: all var(--transition);
}

.portfolio-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.portfolio-featured {
    grid-column: 1 / -1;
    grid-row: 1;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.05), rgba(6, 182, 212, 0.05));
    border-color: rgba(99, 102, 241, 0.2);
}

.portfolio-tag {
    display: inline-block;
    padding: 4px 12px;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 100px;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--accent-1);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 16px;
}

.portfolio-card h3 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.portfolio-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 20px;
}

.portfolio-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.portfolio-tech span {
    padding: 4px 10px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border);
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ---- Contact ---- */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: start;
}

.contact-info h2 {
    font-size: clamp(2rem, 3.5vw, 2.8rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 20px;
    line-height: 1.15;
}

.contact-info p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 32px;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.contact-link {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color var(--transition);
}

.contact-link:hover {
    color: var(--accent-1);
}

.contact-form {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    transition: border-color var(--transition);
    outline: none;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--accent-1);
}

.form-group select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2355556a' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    cursor: pointer;
}

.form-group select option {
    background: var(--bg-card);
    color: var(--text-primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* ---- Footer ---- */
.footer {
    padding: 48px 0;
    border-top: 1px solid var(--border);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    text-align: center;
}

.footer-logo {
    font-family: var(--font-mono);
    font-size: 1rem;
    font-weight: 500;
}

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

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    transition: color var(--transition);
}

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

.footer-copy {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ---- Animations ---- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(24px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

@keyframes scrollPulse {
    0%, 100% {
        opacity: 0.3;
        transform: scaleY(0.6);
        transform-origin: top;
    }
    50% {
        opacity: 1;
        transform: scaleY(1);
    }
}

/* ---- Scroll Animations ---- */
.section {
    opacity: 0;
    transform: translateY(32px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.section.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ---- Responsive ---- */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    .about-tech {
        position: static;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: rgba(10, 10, 15, 0.95);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-bottom: 1px solid var(--border);
        flex-direction: column;
        padding: 24px;
        gap: 16px;
    }
    .nav-links.open {
        display: flex;
    }
    .nav-toggle {
        display: flex;
    }
    .hero-title {
        font-size: 2.2rem;
    }
    .hero-subtitle {
        font-size: 1rem;
    }
    .hero-actions {
        flex-direction: column;
    }
    .hero-stats {
        flex-wrap: wrap;
        gap: 16px;
    }
    .stat-divider {
        display: none;
    }
    .services-grid {
        grid-template-columns: 1fr;
    }
    .portfolio-grid {
        grid-template-columns: 1fr 1fr;
    }
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    .section {
        padding: 80px 0;
    }
    .scroll-indicator {
        display: none;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }
    .hero-title {
        font-size: 1.8rem;
    }
    .service-card,
    .portfolio-card,
    .contact-form {
        padding: 24px;
    }
    .portfolio-grid {
        grid-template-columns: 1fr;
    }
}