/*
 * experience.css — Experience page styles
 * Shihui Ruan · Portfolio
 *
 * Sections:
 *  1.  Design tokens — light (default) + dark override
 *  2.  Reset & base
 *  3.  Accessibility utilities
 *  4.  Scroll progress bar
 *  5.  Topbar & navigation
 *  6.  Mobile menu
 *  7.  Layout helpers
 *  8.  Page header
 *  9.  Timeline
 * 10.  Certificates
 * 11.  Skills
 * 12.  Footer
 * 13.  Reveal & boot animations
 * 14.  Responsive overrides
 */


/* ══════════════════════════════════════════════════════
   1. DESIGN TOKENS  (same palette as index.css)
   ══════════════════════════════════════════════════════ */
:root {
  --bg:        #FAFAF8;
  --bg-alt:    #F2F1EE;
  --surface:   #FFFFFF;
  --border:    #E4E2DE;
  --border-str:#C9C7C1;

  --text:      #1C1B18;   /* ~17:1 ✓ */
  --text-2:    #5C5A54;   /* ~6.5:1 ✓ */
  --text-3:    #96948F;   /* decorative / UI labels only */

  --accent:    #A3620A;   /* 5.1:1 on #FAFAF8 ✓ */
  --accent-2:  #7C4909;
  --on-accent: #FFFFFF;

  --font-display: "Bricolage Grotesque", system-ui, sans-serif;
  --font-body:    "DM Sans", system-ui, sans-serif;
  --radius: 12px;
}

[data-theme="dark"] {
  --bg:        #111110;
  --bg-alt:    #1A1916;
  --surface:   #222120;
  --border:    #2E2C28;
  --border-str:#46443E;

  --text:      #EDEBE7;
  --text-2:    #A8A59F;
  --text-3:    #6A6760;

  --accent:    #F0A932;
  --accent-2:  #D4902C;
  --on-accent: #111110;
}


/* ══════════════════════════════════════════════════════
   2. RESET & BASE
   ══════════════════════════════════════════════════════ */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; color-scheme: light dark; }
[data-theme="light"] { color-scheme: light; }
[data-theme="dark"]  { color-scheme: dark; }

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.4s ease, color 0.4s ease;
}


/* ══════════════════════════════════════════════════════
   3. ACCESSIBILITY UTILITIES
   ══════════════════════════════════════════════════════ */
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  z-index: 200;
  padding: 10px 20px;
  background: var(--accent);
  color: var(--on-accent);
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: 0 0 var(--radius) var(--radius);
  text-decoration: none;
  transition: top 0.2s ease;
}
.skip-link:focus { top: 0; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}


/* ══════════════════════════════════════════════════════
   4. SCROLL PROGRESS BAR
   ══════════════════════════════════════════════════════ */
#scroll-bar {
  position: fixed;
  top: 0; left: 0;
  width: 0%;
  height: 2px;
  background: var(--accent);
  z-index: 100;
  transition: width 0.1s linear;
}


/* ══════════════════════════════════════════════════════
   5. TOPBAR & NAVIGATION
   ══════════════════════════════════════════════════════ */
.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 60;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px clamp(20px, 4vw, 44px);
  background: color-mix(in srgb, var(--bg) 84%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.35s ease, background-color 0.4s ease;
}
.topbar.scrolled { border-bottom-color: var(--border); }

.brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--text);
  text-decoration: none;
}
.brand .mark { color: var(--accent); }

.main-nav { display: none; gap: 28px; }
.main-nav a {
  font-size: 0.9rem;
  color: var(--text-2);
  text-decoration: none;
  position: relative;
  padding: 4px 0;
  transition: color 0.22s ease;
}
.main-nav a::after {
  content: "";
  position: absolute; left: 0; bottom: -2px;
  width: 0; height: 2px;
  border-radius: 2px;
  background: var(--accent);
  transition: width 0.25s ease;
}
.main-nav a:hover,
.main-nav a[aria-current="page"] { color: var(--text); }
.main-nav a:hover::after,
.main-nav a[aria-current="page"]::after { width: 100%; }

.topbar-right { display: flex; align-items: center; gap: 8px; }

.theme-btn {
  width: 38px; height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  background: var(--bg-alt);
  color: var(--text);
  border-radius: 999px;
  cursor: pointer;
  transition: border-color 0.22s ease, color 0.22s ease, background-color 0.4s ease;
}
.theme-btn:hover { border-color: var(--accent); color: var(--accent); }
.theme-btn svg  { width: 17px; height: 17px; display: block; }

.ico-sun  { display: none; }
.ico-moon { display: block; }
[data-theme="dark"] .ico-sun  { display: block; }
[data-theme="dark"] .ico-moon { display: none; }


/* ══════════════════════════════════════════════════════
   6. MOBILE MENU
   ══════════════════════════════════════════════════════ */
.menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.22s ease, color 0.22s ease;
}
.menu-toggle:hover { border-color: var(--accent); color: var(--accent); }
.menu-toggle svg  { display: block; }

@media (min-width: 860px) {
  .main-nav    { display: flex; }
  .menu-toggle { display: none; }
}

@media (max-width: 859px) {
  .main-nav {
    flex-direction: column;
    position: fixed;
    top: 58px; left: 0; right: 0;
    background: color-mix(in srgb, var(--bg) 96%, transparent);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 8px 0 16px;
    gap: 0;
    z-index: 55;
    display: none;
  }
  .main-nav.is-open { display: flex; }
  .main-nav a { padding: 12px clamp(20px, 5vw, 44px); font-size: 1rem; }
  .main-nav a::after { display: none; }
}


/* ══════════════════════════════════════════════════════
   7. LAYOUT HELPERS
   ══════════════════════════════════════════════════════ */
main { position: relative; z-index: 10; }

.wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 clamp(20px, 5vw, 44px);
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 22px;
}
.eyebrow::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
  max-width: 90px;
}

/* Inner section label (below top-level sections) */
.section-label {
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 28px;
}


/* ══════════════════════════════════════════════════════
   8. PAGE HEADER
   ══════════════════════════════════════════════════════ */
.page-header {
  padding: 140px 0 56px;
  position: relative;
  z-index: 10;
}
.page-header h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.4rem, 7vw, 5rem);
  line-height: 1.02;
  letter-spacing: -0.025em;
  margin-bottom: 16px;
}
.page-header h1 .accent { color: var(--accent); }
.page-header .sub {
  font-size: 1.06rem;
  color: var(--text-2);
  max-width: 520px;
  line-height: 1.65;
}


/* ══════════════════════════════════════════════════════
   9. TIMELINE
   ══════════════════════════════════════════════════════ */
.timeline-section {
  padding-bottom: clamp(56px, 8vw, 90px);
}

.tl-list {
  position: relative;
  padding-left: 32px;
}

/* Vertical connecting line */
.tl-list::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 12px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--accent) 0%, var(--border) 60%, transparent 100%);
}

/* Timeline item */
.tl-item {
  position: relative;
  margin-bottom: 16px;
}
.tl-item:last-child { margin-bottom: 0; }

/* Dot on the line */
.tl-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 22px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--border-str);
  transition: border-color 0.25s ease;
  z-index: 1;
}

/* Current role — accent-colored dot with subtle ring */
.tl-item.is-current::before {
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 16%, transparent);
}

/* Card */
.tl-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 26px 28px;
  transition: border-color 0.25s ease, transform 0.25s ease;
}
.tl-item:hover .tl-card { border-color: var(--border-str); }
.tl-item.is-current:hover .tl-card { border-color: var(--accent); }

/* Card internal layout */
.tl-card-header { margin-bottom: 16px; }

.tl-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}

.tl-date {
  font-size: 0.77rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent);
  border-radius: 999px;
  padding: 3px 11px;
}

.tl-location {
  font-size: 0.78rem;
  color: var(--text-3);
}

.tl-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.3rem;
  letter-spacing: -0.01em;
  line-height: 1.2;
  margin-bottom: 4px;
}

.tl-org {
  font-size: 0.9rem;
  color: var(--text-2);
  font-weight: 500;
}

.type-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-3);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px 8px;
  margin-left: 8px;
  vertical-align: middle;
}

.tl-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 7px;
  margin-bottom: 16px;
}
.tl-bullets li {
  font-size: 0.94rem;
  color: var(--text-2);
  line-height: 1.6;
  padding-left: 18px;
  position: relative;
}
.tl-bullets li::before {
  content: "–";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

.tl-note {
  font-size: 0.88rem;
  color: var(--text-3);
  font-style: italic;
  margin-bottom: 14px;
}

.tl-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  padding-top: 4px;
}
.tl-tags span {
  font-size: 0.73rem;
  font-weight: 500;
  color: var(--text-3);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px 10px;
}


/* ══════════════════════════════════════════════════════
   10. CERTIFICATES
   ══════════════════════════════════════════════════════ */
.certs-section {
  padding-bottom: clamp(48px, 7vw, 80px);
}

.cert-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.cert-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  transition: border-color 0.22s ease;
}
.cert-card:hover { border-color: var(--border-str); }

.cert-year {
  font-size: 0.74rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: 6px;
}
.cert-name {
  font-size: 0.92rem;
  color: var(--text);
  font-weight: 500;
  line-height: 1.45;
}


/* ══════════════════════════════════════════════════════
   11. SKILLS
   ══════════════════════════════════════════════════════ */
.skills-section {
  padding-bottom: clamp(72px, 10vw, 110px);
}

.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.skills-block {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
  transition: border-color 0.22s ease;
}
.skills-block:hover { border-color: var(--border-str); }

.skills-block h3 {
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 14px;
}

.skills-block ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.skills-block ul li {
  font-size: 0.9rem;
  color: var(--text-2);
  padding: 2px 0;
}


/* ══════════════════════════════════════════════════════
   12. FOOTER
   ══════════════════════════════════════════════════════ */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px clamp(20px, 5vw, 44px);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 0.82rem;
  color: var(--text-3);
  position: relative;
  z-index: 10;
}
.footer .accent { color: var(--accent); }
.footer a {
  color: var(--text-2);
  text-decoration: none;
  transition: color 0.22s ease;
}
.footer a:hover { color: var(--accent); }


/* ══════════════════════════════════════════════════════
   13. ANIMATIONS
   ══════════════════════════════════════════════════════ */
.boot {
  opacity: 0;
  transform: translateY(16px);
}
.boot.on {
  animation: rise 0.7s cubic-bezier(0.2, 0, 0.1, 1) forwards;
}
@keyframes rise {
  to { opacity: 1; transform: translateY(0); }
}

/* Reveal: timeline cards slide in from the left */
.reveal {
  opacity: 0;
  transform: translateX(-12px);
  transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.2, 0, 0.1, 1);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateX(0);
}

/* Cert and skill cards fade up instead of sliding */
.cert-card.reveal,
.skills-block.reveal {
  transform: translateY(16px);
}
.cert-card.reveal.is-visible,
.skills-block.reveal.is-visible {
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
  .reveal, .boot { opacity: 1 !important; transform: none !important; }
}


/* ══════════════════════════════════════════════════════
   14. RESPONSIVE
   ══════════════════════════════════════════════════════ */

/* ── Tablet ≥ 640px ── */
@media (min-width: 640px) {
  .cert-grid   { grid-template-columns: repeat(3, 1fr); }
  .skills-grid { grid-template-columns: 1fr 1fr; }
}

/* ── Desktop ≥ 900px ── */
@media (min-width: 900px) {
  .skills-grid { grid-template-columns: 1fr 1fr 1fr; }
}