/* ── Light mode (default) ── */
:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-2: #f1f5f9;
  --text: #0f172a;
  --muted: #64748b;
  --border: rgba(15, 23, 42, 0.1);
  --accent: #0ea5e9;
  --accent-2: #7c3aed;
  --radius-lg: 24px;
  --radius-md: 16px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.07);
  --overlay-fade: rgba(241, 245, 249, 0.7);
  --h1-from: #1e293b;
  --h1-to: #64748b;
}

/* ── Dark mode ── */
html.dark {
  --bg: #0f172a;
  --surface: #111827;
  --surface-2: #1f2937;
  --text: #f8fafc;
  --muted: #94a3b8;
  --border: rgba(148, 163, 184, 0.22);
  --accent: #38bdf8;
  --accent-2: #a78bfa;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  --overlay-fade: rgba(17, 24, 39, 0.55);
  --h1-from: #f8fafc;
  --h1-to: #94a3b8;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  line-height: 1.6;
  transition: background 0.2s, color 0.2s;
}

/* ── Header ── */

header {
  padding: 64px 24px 52px;
  border-bottom: 1px solid var(--border);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 36px;
}

.identity h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  background: linear-gradient(135deg, var(--h1-from) 0%, var(--h1-to) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 6px;
}

.eng-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 12px;
}

.bio {
  font-size: 0.925rem;
  color: var(--muted);
  max-width: 680px;
  line-height: 1.75;
  margin-bottom: 16px;
}

.focus-areas {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  max-width: 720px;
  margin-bottom: 14px;
}

.focus-area {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--accent-2);
  background: color-mix(in srgb, var(--accent-2) 8%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent-2) 22%, transparent);
  padding: 5px 12px;
  border-radius: 100px;
  line-height: 1.3;
}

.remote-line {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent-2);
  border: 1px solid color-mix(in srgb, var(--accent-2) 35%, transparent);
  background: color-mix(in srgb, var(--accent-2) 7%, transparent);
  padding: 5px 14px;
  border-radius: 100px;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

nav a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 7px 18px;
  border-radius: 100px;
  text-decoration: none;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}

nav a:hover {
  color: var(--text);
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, transparent);
}

nav a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

nav .nav-link-locked::before {
  content: "🔒 ";
  font-size: 0.75rem;
}

/* ── Theme toggle ── */

.theme-toggle {
  position: fixed;
  top: 16px;
  right: 16px;
  z-index: 100;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow);
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.theme-toggle:hover {
  border-color: var(--accent);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* ── Main ── */

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 52px 24px 96px;
}

.section-eyebrow {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 28px;
}

/* ── Grid ── */

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

@media (max-width: 920px) {
  .project-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 580px) {
  .project-grid {
    grid-template-columns: 1fr;
  }

  header {
    padding: 40px 20px 36px;
  }

  main {
    padding: 36px 20px 60px;
  }
}

/* ── Card ── */

.project-card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  text-decoration: none;
  color: var(--text);
  box-shadow: var(--shadow);
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.13);
  border-color: color-mix(in srgb, var(--accent) 40%, transparent);
}

html.dark .project-card:hover {
  box-shadow: 0 32px 80px rgba(0, 0, 0, 0.5);
}

.project-card:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ── iframe Preview ── */

.preview {
  position: relative;
  width: 100%;
  padding-top: 62%;
  background: var(--surface-2);
  overflow: hidden;
}

.preview iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 200%;
  height: 200%;
  transform: scale(0.5);
  transform-origin: top left;
  pointer-events: none;
  border: none;
}

.preview-overlay {
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(to bottom, transparent 55%, var(--overlay-fade) 100%);
}

/* ── Card Body ── */

.card-body {
  padding: 20px 22px 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
}

.card-body h3 {
  font-size: 0.975rem;
  font-weight: 700;
  line-height: 1.3;
}

.card-body p {
  font-size: 0.83rem;
  color: var(--muted);
  line-height: 1.65;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  margin-top: 2px;
}

.tag {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 9%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent);
  padding: 3px 9px;
  border-radius: 100px;
}

.view-link {
  display: block;
  margin-top: auto;
  padding-top: 14px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent);
}

/* ── Footer ── */

footer {
  border-top: 1px solid var(--border);
  padding: 24px;
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
}