/* =========================================================================
   Peter's Projects · styles.css
   "High-end visual" aesthetic on a zero-build static stack.
   Restraint + layered depth: precise type scale, soft multi-layer shadows,
   generous whitespace, per-category accent colors (set inline via --accent).
   ========================================================================= */

/* ---- Design tokens : LIGHT (default) ---- */
:root,
[data-theme="light"] {
  --primary:        #4F46E5;
  --primary-soft:   #EEF0FF;
  --grad-a:         #4F46E5;   /* hero gradient stops */
  --grad-b:         #7C3AED;
  --grad-c:         #EC4899;

  --background:     #FAFAFB;
  --bg-glow:        rgba(124, 58, 237, .10);
  --on-background:  #16131F;
  --surface:        #FFFFFF;
  --surface-2:      #F4F3F8;
  --on-surface:     #1B1830;
  --muted:          #5C5870;
  --muted-2:        #8A8699;

  --border:         #E7E5EE;
  --border-strong:  #D6D3E0;

  --accent:         #4F46E5;   /* overridden per-section inline */

  --shadow-sm: 0 1px 2px rgba(20,16,40,.05), 0 2px 6px rgba(20,16,40,.04);
  --shadow-md: 0 4px 12px rgba(20,16,40,.07), 0 12px 28px rgba(20,16,40,.06);
  --shadow-lg: 0 8px 24px rgba(20,16,40,.10), 0 24px 56px rgba(20,16,40,.10);

  --radius-sm: 10px;
  --radius:    18px;
  --radius-lg: 28px;

  --maxw: 1120px;
  --font-body: "Roboto Flex", "Noto Sans TC", system-ui, -apple-system, sans-serif;
}

/* ---- Design tokens : DARK ---- */
[data-theme="dark"] {
  --primary:        #A5B4FC;
  --primary-soft:   #1E1B33;
  --grad-a:         #818CF8;
  --grad-b:         #C084FC;
  --grad-c:         #F472B6;

  --background:     #0B0A11;
  --bg-glow:        rgba(129, 140, 248, .14);
  --on-background:  #ECEAF5;
  --surface:        #15131F;
  --surface-2:      #1D1A2A;
  --on-surface:     #F1EFF8;
  --muted:          #A9A4BD;
  --muted-2:        #76728C;

  --border:         #272336;
  --border-strong:  #353048;

  --shadow-sm: 0 1px 2px rgba(0,0,0,.4);
  --shadow-md: 0 6px 20px rgba(0,0,0,.5);
  --shadow-lg: 0 12px 40px rgba(0,0,0,.6);
}

/* ---- Reset / base ---- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--background);
  color: var(--on-background);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background .25s, color .25s;
  overflow-x: hidden;
}
/* soft glow behind the top of the page */
body::before {
  content: "";
  position: fixed;
  inset: -20% 0 auto 0;
  height: 60vh;
  background: radial-gradient(60% 70% at 50% 0%, var(--bg-glow), transparent 70%);
  pointer-events: none;
  z-index: 0;
}
a { color: inherit; text-decoration: none; }
.material-symbols-rounded {
  font-variation-settings: "FILL" 0, "wght" 400, "GRAD" 0, "opsz" 24;
  line-height: 1;
  user-select: none;
}

/* ---- App bar ---- */
.appbar {
  position: sticky;
  top: 0;
  z-index: 30;
  background: color-mix(in srgb, var(--background) 82%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.appbar__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 800;
  font-size: 1.12rem;
  letter-spacing: -.01em;
  color: var(--on-surface);
  min-width: 0;
  overflow: hidden;
}
.brand__logo {
  color: var(--primary);
  flex: 0 0 auto;
  font-variation-settings: "FILL" 1, "wght" 500, "GRAD" 0, "opsz" 24;
}
.brand__name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.appbar__actions { margin-left: auto; display: flex; align-items: center; gap: 6px; flex: 0 0 auto; }

/* ---- Icon button ---- */
.icon-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  border-radius: 999px;
  padding: 8px 12px;
  cursor: pointer;
  font: inherit;
  transition: background .15s, color .15s, border-color .15s;
}
.icon-btn:hover { background: var(--surface-2); color: var(--on-surface); }
.icon-btn__txt { font-size: .85rem; font-weight: 600; }
.icon-btn .material-symbols-rounded { font-size: 20px; }

/* ---- Sticky section nav (scrollspy) ---- */
.sectionnav {
  position: sticky;
  top: 57px;
  z-index: 25;
  background: color-mix(in srgb, var(--background) 86%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.sectionnav__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 10px 16px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
}
.sectionnav__inner::-webkit-scrollbar { display: none; }
.navpill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex: 0 0 auto;
  padding: 8px 15px;
  border-radius: 999px;
  font-size: .85rem;
  font-weight: 600;
  color: var(--muted);
  border: 1px solid var(--border);
  background: var(--surface);
  white-space: nowrap;
  cursor: pointer;
  transition: background .15s, color .15s, border-color .15s, transform .15s;
}
.navpill .material-symbols-rounded { font-size: 18px; color: var(--accent); }
.navpill:hover { transform: translateY(-1px); border-color: var(--border-strong); }
.navpill--active {
  color: #fff;
  background: var(--accent);
  border-color: transparent;
}
.navpill--active .material-symbols-rounded { color: #fff; }

/* ---- Section scaffolding ---- */
.section {
  position: relative;
  z-index: 1;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 64px 20px 8px;
  scroll-margin-top: 120px;
}
.section-head { margin-bottom: 24px; }
.section-head h2 {
  position: relative;
  margin: 0 0 8px;
  padding-left: 16px;
  font-size: clamp(1.5rem, 3.4vw, 2rem);
  font-weight: 800;
  letter-spacing: -.02em;
  color: var(--on-surface);
}
/* accent bar to the left of each category heading */
.section--cards .section-head h2::before {
  content: "";
  position: absolute;
  left: 0; top: .12em; bottom: .12em;
  width: 5px;
  border-radius: 999px;
  background: var(--accent);
}
.section-head__sub {
  margin: 0;
  padding-left: 16px;
  max-width: 62ch;
  font-size: .98rem;
  line-height: 1.55;
  color: var(--muted);
}
.section--cards .section-head__sub {
  font-weight: 600;
  color: var(--accent);
  letter-spacing: .01em;
}

/* ---- HERO ---- */
.section--hero { padding-top: 64px; padding-bottom: 8px; }
.section--hero .section-head h2 {
  padding-left: 0;
  font-size: clamp(2.4rem, 7vw, 4rem);
  font-weight: 900;
  line-height: 1.05;
  background: linear-gradient(105deg, var(--grad-a), var(--grad-b) 55%, var(--grad-c));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.section--hero .section-head__sub {
  padding-left: 0;
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 52ch;
}
.hero__stats {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}
.hero__stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 26px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  box-shadow: var(--shadow-sm);
  min-width: 120px;
}
.hero__stat-value {
  font-size: 2.4rem;
  font-weight: 900;
  letter-spacing: -.02em;
  color: var(--primary);
  font-variant-numeric: tabular-nums;
  line-height: 1.05;
}
.hero__stat-label { font-size: .85rem; font-weight: 600; color: var(--muted); }

/* ---- CARDS grid (external links) ---- */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 18px;
}
.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 22px 18px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 10px;
  overflow: hidden;
  transition: box-shadow .2s, transform .2s, border-color .2s;
}
/* accent strip that grows on hover */
.card::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 4px;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .22s ease;
}
.card:hover,
.card:focus-visible {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
  outline: none;
}
.card:hover::before,
.card:focus-visible::before { transform: scaleY(1); }
.card__top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 10px;
}
.card__title {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -.01em;
  line-height: 1.35;
  color: var(--on-surface);
}
.card__go {
  flex: 0 0 auto;
  font-size: 20px;
  color: var(--muted-2);
  transition: color .2s, transform .2s;
}
.card:hover .card__go,
.card:focus-visible .card__go {
  color: var(--accent);
  transform: translate(2px, -2px);
}
.card__summary {
  margin: 0;
  font-size: .92rem;
  line-height: 1.6;
  color: var(--muted);
}

/* ---- Footer ---- */
.footer {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 40px 20px;
  margin-top: 32px;
  color: var(--muted-2);
  font-size: .85rem;
  border-top: 1px solid var(--border);
}
.footer__social {
  display: flex;
  justify-content: center;
  margin-bottom: 16px;
}
.social-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 18px;
  border-radius: 999px;
  font-weight: 600;
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--border);
  transition: color .15s, border-color .15s, transform .15s, box-shadow .15s;
}
.social-link svg { flex: 0 0 auto; }
.social-link:hover {
  color: #0A66C2;                       /* LinkedIn blue on hover */
  border-color: color-mix(in srgb, #0A66C2 45%, var(--border));
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

/* ---- Responsive ---- */
@media (max-width: 640px) {
  .grid { grid-template-columns: 1fr; }
  .section { padding-top: 48px; }
  .hero__stat { flex: 1 1 40%; padding: 16px 20px; }
}
@media (max-width: 380px) {
  .appbar__inner, .sectionnav__inner, .section { padding-left: 14px; padding-right: 14px; }
}

/* Respect reduced-motion */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}