/* ============================================================
   Code Studio — core theme
   Light, dynamic IDE / code-editor aesthetic.
   Single source of truth for tokens, layout, nav, footer,
   buttons, and shared animations. See Theme/studio.md.
   ============================================================ */

:root {
    /* surfaces */
    --bg: #fbfbfd;
    --bg-2: #f3f5f9;
    --chrome: #f6f8fb;
    --surface: #ffffff;
    --line: #e6e9f0;
    --line-strong: #d3d8e4;

    /* text */
    --ink: #1b1f2a;
    --ink-soft: #515a6b;
    --ink-faint: #8b93a4;

    /* syntax tokens */
    --kw: #9b2bd6;
    --fn: #b0750a;
    --str: #c0392b;
    --num: #0a9e6e;
    --type: #1d8aa6;
    --var: #2563eb;
    --comment: #16a34a;

    /* brand */
    --accent: #2563eb;
    --accent-rgb: 37, 99, 235;
    --grad: linear-gradient(120deg, #2563eb, #06b6d4 50%, #9b2bd6);

    /* type */
    --font-display: 'JetBrains Mono', monospace;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    /* metrics */
    --nav-height: 70px;
    --maxw: 1180px;
    --radius: 12px;
    --radius-sm: 8px;
    --transition: 0.28s cubic-bezier(0.16, 1, 0.3, 1);
}

/* ============ RESET / BASE ============ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-height) + 20px); }

body {
    font-family: var(--font-body);
    background:
        radial-gradient(circle at 12% 0%, rgba(37, 99, 235, 0.05), transparent 42%),
        radial-gradient(circle at 88% 100%, rgba(155, 43, 214, 0.05), transparent 42%),
        var(--bg);
    background-attachment: fixed;
    color: var(--ink-soft);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    overflow-x: clip;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

.section { padding: 72px 0; }

/* ============ SCROLL PROGRESS ============ */
.scroll-progress {
    position: fixed; top: 0; left: 0; height: 3px; width: 0%;
    background: var(--grad); background-size: 200% auto;
    animation: slideGrad 5s linear infinite;
    z-index: 2000;
}

/* ============ NAVBAR ============ */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; height: var(--nav-height);
    display: flex; align-items: center;
    background: rgba(246, 248, 251, 0.72);
    border-bottom: 1px solid transparent;
    z-index: 1000; transition: var(--transition);
}
.navbar.scrolled {
    backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border-bottom-color: var(--line);
    box-shadow: 0 4px 24px rgba(20, 30, 60, 0.05);
}
.nav-container {
    width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px;
    display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
    display: inline-flex; align-items: center; gap: 8px;
    font-family: var(--font-display); font-weight: 800; font-size: 1.25rem;
    color: var(--ink); letter-spacing: -0.5px;
}
.nav-logo::before {
    content: '\f121'; font-family: 'Font Awesome 6 Free'; font-weight: 900;
    font-size: 1rem; color: var(--accent);
}
.logo-bracket { color: var(--kw); }
.logo-dot {
    background: var(--grad); background-size: 200% auto;
    -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: slideGrad 5s linear infinite;
}

.nav-links { display: flex; align-items: center; gap: 8px; }
.nav-link {
    position: relative; font-family: var(--font-display); font-size: 0.86rem;
    font-weight: 500; color: var(--ink-soft); padding: 8px 12px; border-radius: var(--radius-sm);
    transition: color var(--transition), background var(--transition);
}
.nav-link::before { content: '#'; color: var(--ink-faint); margin-right: 2px; }
.nav-link::after {
    content: ''; position: absolute; left: 12px; right: 12px; bottom: 2px; height: 2px; width: 0;
    background: var(--grad); background-size: 200% auto;
    animation: slideGrad 5s linear infinite; transition: width var(--transition);
}
.nav-link:hover, .nav-link.active { color: var(--accent); background: var(--bg-2); }
.nav-link:hover::after, .nav-link.active::after { width: calc(100% - 24px); }
.nav-link.external::before { content: '\2197'; margin-right: 4px; }

.nav-toggle {
    display: none; flex-direction: column; gap: 5px; background: none;
    border: none; cursor: pointer; padding: 6px; z-index: 1100;
}
.nav-toggle span {
    display: block; width: 24px; height: 2px; background: var(--ink);
    border-radius: 2px; transition: var(--transition);
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-overlay {
    position: fixed; inset: 0; background: rgba(20, 25, 40, 0.4);
    backdrop-filter: blur(2px); opacity: 0; pointer-events: none;
    transition: opacity var(--transition); z-index: 900;
}
.nav-overlay.show { opacity: 1; pointer-events: auto; }

/* ============ BUTTONS ============ */
.btn {
    display: inline-flex; align-items: center; gap: 9px;
    font-family: var(--font-display); font-weight: 600; font-size: 0.92rem;
    padding: 12px 22px; border-radius: var(--radius-sm); cursor: pointer;
    border: 1px solid transparent; transition: var(--transition); white-space: nowrap;
}
.btn i { font-size: 0.9em; }
.btn-primary {
    background: var(--accent); color: #fff;
    box-shadow: 0 6px 18px rgba(var(--accent-rgb), 0.25);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 26px rgba(var(--accent-rgb), 0.35);
}
.btn-outline {
    background: var(--surface); color: var(--ink); border-color: var(--line-strong);
}
.btn-outline:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-2px); }

/* ============ SECTION HEADER ============ */
.section-header { text-align: center; max-width: 640px; margin: 0 auto 48px; }
.section-tag {
    display: inline-block; font-family: var(--font-mono); font-size: 0.8rem;
    color: var(--kw); letter-spacing: 0.02em; margin-bottom: 14px;
}
.section-tag::before { content: '<'; color: var(--ink-faint); }
.section-tag::after { content: '>'; color: var(--ink-faint); }
.section-title {
    font-family: var(--font-display); font-weight: 800; color: var(--ink);
    font-size: clamp(1.7rem, 4vw, 2.4rem); letter-spacing: -0.5px;
}
.section-title::before { content: 'function '; color: var(--kw); font-weight: 500; font-size: 0.62em; }
.section-title::after { content: '()'; color: var(--ink-faint); font-weight: 500; }
.section-line {
    width: 64px; height: 4px; margin: 16px auto 0; border-radius: 4px;
    background: var(--grad); background-size: 200% auto;
    animation: slideGrad 5s linear infinite;
}

/* gradient text helper */
.name-highlight {
    background: var(--grad); background-size: 200% auto;
    -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: slideGrad 6s linear infinite;
}

/* ============ FOOTER ============ */
.footer {
    background: var(--chrome); border-top: 1px solid var(--line);
    padding: 40px 0;
}
.footer-content {
    display: flex; flex-direction: column; align-items: center; gap: 16px; text-align: center;
}
.footer-logo {
    display: inline-flex; align-items: center; gap: 8px;
    font-family: var(--font-display); font-weight: 800; font-size: 1.3rem; color: var(--ink);
}
.footer-logo::before {
    content: '\f121'; font-family: 'Font Awesome 6 Free'; font-weight: 900;
    font-size: 1rem; color: var(--accent);
}
.footer-socials { display: flex; gap: 16px; }
.footer-socials a {
    width: 44px; height: 44px; display: grid; place-items: center;
    background: var(--surface); border: 1px solid var(--line);
    border-radius: var(--radius-sm); color: var(--ink-soft);
    font-size: 1rem; transition: var(--transition);
}
.footer-socials a:hover {
    color: var(--accent); border-color: var(--accent); transform: translateY(-3px);
}
.footer-copy { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-faint); }
.footer-copy::before { content: '// '; color: var(--comment); }
.footer-copy a { color: var(--accent); }

/* ============ ANIMATIONS ============ */
@keyframes slideGrad { to { background-position: 200% center; } }
@keyframes blink { 50% { opacity: 0; } }
@keyframes floatChip { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }
@keyframes pulse { 0% { transform: scale(1); opacity: 0.5; } 100% { transform: scale(2.6); opacity: 0; } }
@keyframes revealUp { to { opacity: 1; transform: translateY(0); } }

.typing-cursor {
    display: inline-block; width: 2px; height: 1em; margin-left: 1px;
    background: var(--accent); transform: translateY(2px);
    animation: blink 1s step-end infinite;
}
.float-chip { animation: floatChip 5s ease-in-out infinite; }

.reveal-up { opacity: 0; transform: translateY(20px); animation: revealUp 0.7s forwards; }

.scroll-reveal { opacity: 0; transform: translateY(22px); transition: opacity 0.6s ease, transform 0.6s ease; }
.scroll-reveal.revealed { opacity: 1; transform: translateY(0); }

/* ============ SKILL BAR ============ */
.skill-bar { height: 8px; background: var(--bg-2); border: 1px solid var(--line); border-radius: 4px; overflow: hidden; }
.skill-fill {
    display: block; height: 100%; width: 0;
    background: var(--grad); background-size: 200% auto;
    animation: slideGrad 5s linear infinite; border-radius: 4px;
    transition: width 1.1s cubic-bezier(0.16, 1, 0.3, 1);
}

/* ============ RESPONSIVE NAV ============ */
@media (max-width: 768px) {
    .nav-toggle { display: flex; }
    .nav-links {
        position: fixed; top: 0; right: 0; height: 100vh; width: min(78vw, 300px);
        flex-direction: column; align-items: flex-start; justify-content: center;
        gap: 14px; padding: 0 30px; background: var(--surface);
        border-left: 1px solid var(--line); transform: translateX(100%);
        transition: transform var(--transition); z-index: 1000;
    }
    .nav-links.open { transform: translateX(0); }
    .nav-link { font-size: 1.05rem; }
    .nav-link::after { left: 12px; right: auto; }
    .nav-link:hover::after, .nav-link.active::after { width: 40%; }
    .section { padding: 56px 0; }
}

/* ============ REDUCED MOTION ============ */
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
    }
}