/* Reset and Base Styles */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary: #0f172a;
    --primary-light: #1e293b;
    --accent: #0ea5e9;
    --accent-dark: #0284c7;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.1);

    /* Typography */
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Container */
    --container-max: 1200px;

    /* Transitions */
    --transition: 0.2s ease;
    --transition-slow: 0.4s ease;
}

body {
    font-family: var(--font-heading);
    color: var(--text-primary);
    line-height: 1.6;
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

/* ==============================
   HEADER
============================== */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-color);
    padding: 0.875rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    transition: box-shadow var(--transition);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

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

.header-logo,
.header-logo:visited {
    display: flex;
    flex-direction: column;
    text-decoration: none;
    gap: 0.125rem;
}

.name {
    font-size: 1.375rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

.title {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Desktop Nav */
.nav {
    display: flex;
    gap: 0.25rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    padding: 0.375rem 0.75rem;
    border-radius: 0.375rem;
    transition: color var(--transition), background var(--transition);
}

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

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.375rem;
    transition: background var(--transition);
}

.mobile-menu-btn:hover {
    background: var(--bg-secondary);
}

.mobile-menu-btn span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: transform var(--transition), opacity var(--transition);
}

.mobile-menu-btn.open span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.mobile-menu-btn.open span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.open span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Menu */
.mobile-menu {
    display: flex;
    flex-direction: column;
    padding: 0.75rem 0 1rem;
    border-top: 1px solid var(--border-color);
    margin-top: 0.875rem;
    gap: 0.25rem;
}

.mobile-menu[hidden] {
    display: none;
}

.mobile-nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    padding: 0.625rem 0.5rem;
    border-radius: 0.375rem;
    transition: color var(--transition), background var(--transition);
}

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

/* ==============================
   HERO
============================== */
.hero {
    padding: var(--spacing-xl) 0;
    background: var(--bg-primary);
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 80% 60% at 50% -10%, rgba(14, 165, 233, 0.06) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    position: relative;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(14, 165, 233, 0.08);
    border: 1px solid rgba(14, 165, 233, 0.2);
    color: var(--accent-dark);
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0.375rem 0.875rem;
    border-radius: 2rem;
    margin-bottom: var(--spacing-md);
}

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

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.6; transform: scale(0.85); }
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.15;
    color: var(--primary);
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    font-weight: 500;
}

.hero-description {
    font-size: 1.0625rem;
    max-width: 680px;
    margin: 0 auto var(--spacing-md);
    color: var(--text-secondary);
    line-height: 1.75;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-top: var(--spacing-md);
}

/* ==============================
   BUTTONS
============================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.6875rem 1.375rem;
    border-radius: 0.375rem;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all var(--transition);
    border: 1px solid var(--border-color);
    cursor: pointer;
    background: var(--bg-primary);
    color: var(--text-primary);
    white-space: nowrap;
}

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

.btn-primary:hover {
    background: var(--primary-light);
    border-color: var(--primary-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--bg-primary);
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-secondary);
    border-color: #cbd5e1;
    transform: translateY(-1px);
}

.btn-github {
    background: var(--text-primary);
    color: white;
    border-color: var(--text-primary);
}

.btn-github:hover {
    background: var(--primary-light);
    border-color: var(--primary-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-demo {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-demo:hover {
    background: var(--border-color);
    transform: translateY(-1px);
}

.btn-icon {
    flex-shrink: 0;
}

/* ==============================
   SECTION BASE
============================== */
section {
    padding: var(--spacing-xl) 0;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    letter-spacing: -0.01em;
}

/* ==============================
   PROJECTS
============================== */
.projects {
    background: var(--bg-secondary);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-md);
}

.project-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: var(--spacing-md);
    transition: box-shadow var(--transition-slow), border-color var(--transition-slow), transform var(--transition-slow);
}

.project-card:hover {
    box-shadow: var(--shadow-lg);
    border-color: rgba(14, 165, 233, 0.3);
    transform: translateY(-2px);
}

.project-title {
    font-size: 1.1875rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.project-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-size: 0.9375rem;
    line-height: 1.7;
}

.github-stats {
    display: flex;
    gap: 0.5rem;
    margin-bottom: var(--spacing-sm);
    flex-wrap: wrap;
}

.github-stat {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    background: var(--bg-secondary);
    padding: 0.2rem 0.65rem;
    border-radius: 1rem;
    font-size: 0.8125rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.project-stats {
    display: grid;
    gap: 0.375rem;
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

.stat {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    font-size: 0.875rem;
}

.stat-label {
    color: var(--text-secondary);
    font-weight: 500;
    flex-shrink: 0;
}

.stat-value {
    color: var(--text-primary);
    font-weight: 600;
    text-align: right;
}

.project-highlights {
    margin-bottom: var(--spacing-sm);
}

.project-highlights strong {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-size: 0.9375rem;
}

.project-highlights ul {
    list-style: none;
    padding-left: 0;
}

.project-highlights li {
    padding-left: 1.375rem;
    position: relative;
    margin-bottom: 0.3rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

.project-highlights li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #22c55e;
    font-weight: 700;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.375rem;
    margin-bottom: var(--spacing-sm);
}

.tag {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 0.2rem 0.65rem;
    border-radius: 0.25rem;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
    font-family: var(--font-mono);
}

.project-links {
    display: flex;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
}

/* ==============================
   SKILLS
============================== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.skill-category {
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
}

.skill-category-title {
    font-size: 1.0625rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.skill-list {
    list-style: none;
}

.skill-list li {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 0.625rem 0;
    border-bottom: 1px solid var(--border-color);
}

.skill-list li:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.skill-name {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9375rem;
    flex-shrink: 0;
    min-width: 100px;
}

.skill-bar {
    flex: 1;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    overflow: hidden;
    max-width: 120px;
}

.skill-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-dark), var(--accent));
    border-radius: 3px;
    width: 0;
    transition: width 1s ease;
}

.skills-animated .skill-bar-fill {
    width: var(--skill-width);
}

/* ==============================
   ABOUT
============================== */
.about {
    background: var(--bg-secondary);
}

.about-content {
    max-width: 780px;
    margin: 0 auto;
}

.about-content p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    line-height: 1.85;
    font-size: 1.0rem;
}

.about-content p:last-child {
    margin-bottom: 0;
}

/* ==============================
   CONTACT
============================== */
.contact-text {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-size: 1.0625rem;
    max-width: 520px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.7;
}

.contact-links {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    max-width: 480px;
    margin: 0 auto;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.875rem;
    padding: 0.875rem 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.625rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all var(--transition);
}

.contact-link:hover {
    background: white;
    border-color: var(--accent);
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
    color: var(--accent-dark);
}

.contact-icon {
    color: var(--text-secondary);
    flex-shrink: 0;
    transition: color var(--transition);
}

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

/* ==============================
   FOOTER
============================== */
.footer {
    background: var(--primary);
    color: rgba(255, 255, 255, 0.7);
    padding: 1.5rem 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    font-size: 0.875rem;
}

.footer-links {
    display: flex;
    gap: 1.25rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition);
}

.footer-links a:hover {
    color: white;
}

/* ==============================
   BACK TO TOP
============================== */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 42px;
    height: 42px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition);
    z-index: 50;
    opacity: 0;
    transform: translateY(8px);
}

.back-to-top:not([hidden]) {
    opacity: 1;
    transform: translateY(0);
}

.back-to-top[hidden] {
    display: flex; /* override browser hidden so we can animate */
    opacity: 0;
    pointer-events: none;
    transform: translateY(8px);
}

.back-to-top:hover {
    background: var(--primary-light);
    transform: translateY(-2px);
}

/* ==============================
   SCROLL REVEAL
============================== */
.reveal {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.reveal-grid .project-card {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease, transform 0.5s ease, box-shadow 0.4s ease, border-color 0.4s ease;
}

.reveal-grid.visible .project-card {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger children */
.reveal-grid.visible .project-card:nth-child(2) { transition-delay: 0.1s; }
.reveal-grid.visible .project-card:nth-child(3) { transition-delay: 0.2s; }
.reveal-grid.visible .project-card:nth-child(4) { transition-delay: 0.3s; }

/* ==============================
   RESPONSIVE
============================== */
@media (max-width: 768px) {
    .nav {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero-title {
        font-size: 2.125rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-description {
        font-size: 0.9375rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .section-title {
        font-size: 1.625rem;
    }

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

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

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .back-to-top {
        bottom: 1.25rem;
        right: 1.25rem;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-xl: 4rem;
        --spacing-lg: 2.5rem;
    }

    .hero-title {
        font-size: 1.875rem;
    }

    .skill-bar {
        max-width: 90px;
    }
}

/* ==============================
   REDUCED MOTION
============================== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }

    .reveal,
    .reveal-grid .project-card {
        opacity: 1;
        transform: none;
    }

    .skill-bar-fill {
        width: var(--skill-width) !important;
    }
}