/* ============================================================
   Trung Nguyen — Portfolio
   Design system: editorial-quant. One accent, generous space,
   GPU-only motion (transform/opacity).
   ============================================================ */

/* ===== TOKENS ===== */
:root {
  /* Dark (default) */
  --bg: #0B0C10;
  --bg-elev: #13141A;
  --bg-soft: #181A22;

  --text-primary: #EDEBE6;
  --text-secondary: #A8A49A;
  --text-muted: #6A6760;

  /* Single accent — deep institutional emerald */
  --accent: #2E8A65;
  --accent-soft: #1F5C44;
  --accent-glow: rgba(46, 138, 101, 0.14);

  --border: rgba(255, 255, 255, 0.07);
  --border-strong: rgba(255, 255, 255, 0.12);
  --rule: rgba(255, 255, 255, 0.04);

  /* Type stacks. Editorial serif (Instrument), Geist Sans, JetBrains Mono. */
  --serif: 'Instrument Serif', 'Times New Roman', Georgia, serif;
  --sans: 'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  /* Motion */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

[data-theme="light"] {
  --bg: #F4F2EC;
  --bg-elev: #FFFFFF;
  --bg-soft: #ECE9E1;

  --text-primary: #0E0F14;
  --text-secondary: #3A3934;
  --text-muted: #6A675F;

  --accent: #1A5D43;
  --accent-soft: #0F4530;
  --accent-glow: rgba(26, 93, 67, 0.10);

  --border: rgba(0, 0, 0, 0.12);
  --border-strong: rgba(0, 0, 0, 0.20);
  --rule: rgba(0, 0, 0, 0.07);
}

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

html {
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--accent-soft) transparent;
  background: var(--bg);
}

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text-primary);
  font-feature-settings: "ss01", "ss02", "cv11";
  line-height: 1.6;
  min-height: 100dvh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: -0.005em;
}

::selection { background: var(--accent); color: #FFFFFF; }

a { color: inherit; text-decoration: none; }

/* ===== AMBIENT BACKGROUND ===== */
/* One soft mesh gradient on body — subtle, no flicker, no scroll repaint. */
body::before {
  content: "";
  position: fixed;
  inset: -10%;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(900px 600px at 12% 12%, var(--accent-glow), transparent 60%),
    radial-gradient(700px 500px at 92% 88%, rgba(255,255,255,0.04), transparent 60%);
  filter: blur(20px);
  opacity: 0.85;
}

[data-theme="light"] body::before {
  background:
    radial-gradient(900px 600px at 12% 12%, var(--accent-glow), transparent 60%),
    radial-gradient(700px 500px at 92% 88%, rgba(0,0,0,0.025), transparent 60%);
  opacity: 1;
}

/* Particle canvas — dialed down. */
#particleCanvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.55;
}
[data-theme="light"] #particleCanvas { opacity: 0.35; }

/* Legacy decoration nodes — kept harmless so existing HTML doesn't break. */
.bg-blob, .scanlines, .vignette { display: none; }

/* Grain overlay — fixed, non-scrolling, GPU-friendly. */
.grain {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.035;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
}

/* Scroll-progress vertical rail (fixed, on left edge). */
.scroll-rail {
  position: fixed;
  top: 0;
  left: 0;
  width: 2px;
  height: 100dvh;
  z-index: 200;
  pointer-events: none;
}
.scroll-rail::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--border);
}
.scroll-rail-fill {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(180deg, var(--accent), var(--accent-soft));
  transform-origin: top center;
  transform: scaleY(0);
  will-change: transform;
}

/* ===== THEME TOGGLE (refined) ===== */
.theme-toggle {
  position: fixed;
  top: 1.4rem;
  right: 2rem;
  z-index: 210;
  width: 32px;
  height: 56px;
  border-radius: 16px;
  border: 1px solid var(--border-strong);
  background: var(--bg-elev);
  cursor: pointer;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 3px;
  transition: border-color 0.3s var(--ease-out), transform 0.3s var(--ease-out);
}
.theme-toggle:hover { border-color: var(--accent); transform: translateY(-1px); }
.theme-toggle:active { transform: translateY(0) scale(0.97); }

.theme-toggle-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--text-muted);
  transition: transform 0.4s var(--ease-spring), background 0.3s var(--ease-out);
  display: flex;
  align-items: center;
  justify-content: center;
  transform: translateY(0);
}
[data-theme="light"] .theme-toggle-thumb {
  transform: translateY(26px);
  background: var(--accent);
}
.theme-toggle-thumb svg {
  width: 12px;
  height: 12px;
  stroke: var(--bg);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* ===== NAV ===== */
.top-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 1.1rem 3rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--rule);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
}

.top-nav-logo {
  font-family: var(--serif);
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  font-style: italic;
}
.top-nav-logo span { color: var(--accent); font-style: normal; }

.top-nav-links {
  display: flex;
  gap: 1.8rem;
}

.top-nav-links a {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  transition: color 0.25s var(--ease-out);
  position: relative;
  padding: 0.2rem 0;
}
.top-nav-links a:hover { color: var(--text-primary); }
.top-nav-links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: -2px;
  width: 0; height: 1px;
  background: var(--accent);
  transition: width 0.35s var(--ease-out);
}
.top-nav-links a:hover::after,
.top-nav-links a.active::after { width: 100%; }
.top-nav-links a.active { color: var(--accent); }

/* ===== TYPOGRAPHY PRIMITIVES ===== */
.section-tag {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.16em;
  margin-bottom: 1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
}
.section-tag::before {
  content: "";
  width: 22px; height: 1px;
  background: var(--accent);
}

.section-title {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 4.6vw, 4rem);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.02;
  margin-bottom: 3rem;
  color: var(--text-primary);
}
.section-title em {
  font-style: italic;
  color: var(--accent);
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.14em;
}

/* ===== PAGE CONTAINER ===== */
.page-content {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 8rem 3rem 5rem;
  min-height: 100dvh;
}

/* ===== ABOUT ===== */
.about-content {
  display: grid;
  grid-template-columns: 1.7fr 1fr;
  gap: 4rem;
  align-items: start;
}
.about-text p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 1.3rem;
  line-height: 1.85;
  max-width: 62ch;
}
.about-text em {
  font-style: italic;
  color: var(--text-primary);
  font-family: var(--serif);
  font-size: 1.15em;
}
.about-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border-top: 1px solid var(--rule);
  border-left: 1px solid var(--rule);
}
.stat-box {
  background: transparent;
  border: none;
  border-right: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  padding: 1.4rem 1.2rem;
  transition: background 0.3s var(--ease-out);
}
.stat-box:hover { background: var(--accent-glow); }
.stat-num {
  font-family: var(--serif);
  font-size: 2.2rem;
  font-weight: 400;
  font-style: italic;
  color: var(--accent);
  line-height: 1;
}
.stat-label {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-top: 0.5rem;
}

/* ===== EXPERIENCE / TIMELINE ===== */
.timeline {
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-left: 0;
  position: relative;
}
.timeline::before { display: none; }
.tl-item {
  position: relative;
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 2.5rem;
  padding: 2rem 0;
  border-top: 1px solid var(--rule);
  transition: padding-left 0.4s var(--ease-out);
}
.tl-item:last-child { border-bottom: 1px solid var(--rule); }
.tl-item::before { display: none; }
.tl-item::after {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 2px;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.5s var(--ease-out);
}
.tl-item:hover { padding-left: 1.2rem; }
.tl-item:hover::after { transform: scaleY(1); }
.tl-date {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--accent);
  letter-spacing: 0.04em;
  padding-top: 6px;
}
.tl-role {
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 400;
  margin-bottom: 0.2rem;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}
.tl-company {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 0.8rem;
  font-family: var(--mono);
  letter-spacing: 0.01em;
}
.tl-desc {
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.8;
  max-width: 68ch;
}

/* ===== EDUCATION ===== */
.edu-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}
.edu-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 2rem;
  transition: border-color 0.3s var(--ease-out), transform 0.3s var(--ease-out);
  position: relative;
  overflow: hidden;
}
.edu-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--accent), transparent 60%);
  opacity: 0;
  transition: opacity 0.4s var(--ease-out);
}
.edu-card:hover::before { opacity: 1; }
.edu-card:hover { border-color: var(--border-strong); }
.edu-card.expanded { overflow: visible; }

.edu-expandable { cursor: pointer; user-select: none; }
.edu-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
}
.edu-toggle-icon {
  color: var(--text-muted);
  transition: transform 0.6s var(--ease-out), color 0.3s var(--ease-out);
  flex-shrink: 0;
}
.edu-expandable:hover > .edu-card-header .edu-toggle-icon,
.edu-expandable:hover > .edu-subcard-header .edu-toggle-icon { color: var(--accent); }
.edu-expandable.expanded > .edu-card-header .edu-toggle-icon,
.edu-expandable.expanded > .edu-subcard-header .edu-toggle-icon {
  transform: rotate(180deg);
  color: var(--accent);
}
.edu-expandable.expanded { border-color: var(--border-strong); }
.edu-expandable.expanded::before { opacity: 1; }

.edu-dropdown {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.8s var(--ease-out), opacity 0.5s ease;
  opacity: 0;
}
.edu-expandable.expanded > .edu-dropdown {
  max-height: 3000px;
  opacity: 1;
  overflow: visible;
}
.edu-dropdown-inner {
  padding-top: 1.8rem;
  border-top: 1px solid var(--rule);
  margin-top: 1.5rem;
}
.edu-expandable.expanded .edu-dropdown-inner {
  animation: dropdownFadeIn 0.6s var(--ease-out) 0.1s backwards;
}
@keyframes dropdownFadeIn {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

.edu-course-heading {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin: 1.8rem 0 0.8rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.edu-course-heading::before {
  content: "";
  width: 4px; height: 4px;
  background: var(--accent);
  flex-shrink: 0;
}
.edu-dropdown-inner .edu-course-heading:first-child { margin-top: 0; }

.edu-course-table {
  width: 100%;
  border-collapse: collapse;
}
.edu-course-table thead th {
  font-family: var(--mono);
  font-size: 0.66rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  text-align: left;
  padding: 0.55rem 1rem;
  border-bottom: 1px solid var(--rule);
}
.edu-course-table thead th:last-child { text-align: center; width: 70px; }
.edu-course-table tbody tr { transition: background 0.2s; }
.edu-course-table tbody tr:hover { background: var(--accent-glow); }
.edu-course-table tbody td {
  font-size: 0.92rem;
  color: var(--text-secondary);
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--rule);
}
.edu-course-table tbody td:first-child {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--accent);
  white-space: nowrap;
}
.edu-course-table tbody td:last-child {
  text-align: center;
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--text-primary);
}

.edu-gpa-badge {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  margin-top: 2rem;
  padding: 0.7rem 1.4rem;
  background: var(--accent-glow);
  border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
  border-radius: 4px;
}
.edu-gpa-label {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}
.edu-gpa-value {
  font-family: var(--serif);
  font-size: 1.7rem;
  font-style: italic;
  color: var(--accent);
}

.edu-self-sections {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
}
.edu-self-section { margin-bottom: 2rem; }
.edu-self-section:last-child { margin-bottom: 0; }
.edu-self-items { display: flex; flex-direction: column; gap: 0.5rem; }
.edu-self-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.6rem 1rem;
  border-left: 2px solid var(--rule);
  transition: border-left-color 0.3s var(--ease-out), background 0.3s var(--ease-out), padding-left 0.3s var(--ease-out);
  flex-wrap: wrap;
}
.edu-self-item:hover {
  border-left-color: var(--accent);
  background: var(--accent-glow);
  padding-left: 1.2rem;
}
.edu-self-title { font-size: 0.95rem; color: var(--text-primary); font-weight: 500; }
.edu-self-author {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
  flex-shrink: 0;
  margin-left: 1.5rem;
}
.edu-view-cert {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  padding: 0.22rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 3px;
  transition: all 0.3s var(--ease-out);
  white-space: nowrap;
  flex-shrink: 0;
}
.edu-view-cert:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-glow);
}

/* Education subcards */
.edu-subcards-stack { display: flex; flex-direction: column; gap: 0.7rem; }
.edu-subcard {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0;
  cursor: pointer;
  user-select: none;
  transition: border-color 0.3s var(--ease-out), transform 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
  position: relative;
  overflow: hidden;
  width: 100%;
}
.edu-subcard.expanded { overflow: visible; }
.edu-subcard-accent {
  height: 2px;
  background: linear-gradient(90deg, var(--accent), transparent 60%);
  opacity: 0;
  transition: opacity 0.3s var(--ease-out);
}
.edu-subcard:hover .edu-subcard-accent,
.edu-subcard.expanded .edu-subcard-accent { opacity: 1; }
.edu-subcard:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
}
.edu-subcard.expanded {
  border-color: var(--border-strong);
  transform: none;
}
.edu-subcard-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.3rem 1.5rem;
}
.edu-subcard-left { display: flex; align-items: center; gap: 1.2rem; }
.edu-subcard-num {
  font-family: var(--serif);
  font-size: 2rem;
  font-style: italic;
  color: var(--accent);
  opacity: 0.35;
  line-height: 1;
  min-width: 36px;
  transition: opacity 0.3s var(--ease-out);
}
.edu-subcard:hover .edu-subcard-num,
.edu-subcard.expanded .edu-subcard-num { opacity: 0.65; }
.edu-subcard-title {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-primary);
  margin-bottom: 0.15rem;
  transition: color 0.3s var(--ease-out);
}
.edu-subcard:hover .edu-subcard-title,
.edu-subcard.expanded .edu-subcard-title { color: var(--accent); }
.edu-subcard-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--mono);
  letter-spacing: 0.02em;
}
.edu-subcard-right { display: flex; align-items: center; gap: 0.8rem; flex-shrink: 0; }
.edu-subcard-count {
  font-family: var(--mono);
  font-size: 0.66rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  padding: 0.25rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 20px;
  transition: all 0.3s var(--ease-out);
}
.edu-subcard:hover .edu-subcard-count {
  border-color: var(--accent);
  color: var(--accent);
}
.edu-subcard-content {
  border-top: 1px solid var(--rule);
  padding: 1.4rem 1.5rem;
}

.edu-self-status {
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.05em;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  flex-shrink: 0;
  margin-left: 1.5rem;
}
.edu-self-status.completed {
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
}
.edu-self-status.in-progress {
  color: #6F9DD0;
  background: rgba(111, 157, 208, 0.10);
  border: 1px solid rgba(111, 157, 208, 0.25);
}
[data-theme="light"] .edu-self-status.in-progress {
  color: #2A66A8;
  background: rgba(42, 102, 168, 0.08);
  border: 1px solid rgba(42, 102, 168, 0.25);
}

.edu-degree {
  font-family: var(--serif);
  font-size: 1.4rem;
  font-weight: 400;
  letter-spacing: -0.01em;
  margin-bottom: 0.3rem;
}
.edu-school {
  color: var(--accent);
  font-size: 0.95rem;
  font-family: var(--mono);
  letter-spacing: 0.02em;
  margin-bottom: 0.2rem;
}
.edu-year {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  margin-bottom: 1.2rem;
}
.edu-details {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.78;
}

/* ===== PROJECTS ===== */
.projects-section-label {
  font-family: var(--serif);
  font-size: 1.5rem;
  font-style: italic;
  font-weight: 400;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--rule);
  display: flex;
  align-items: center;
  gap: 0.7rem;
}
.projects-section-label::before {
  content: "";
  width: 6px; height: 6px;
  background: var(--accent);
  flex-shrink: 0;
}

.projects-other-dropdown {
  margin-top: 3.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg-elev);
  overflow: hidden;
  transition: border-color 0.3s var(--ease-out);
}
.projects-other-dropdown:hover,
.projects-other-dropdown.expanded { border-color: var(--border-strong); }
.projects-other-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.3rem 1.8rem;
  cursor: pointer;
  user-select: none;
}
.projects-other-header .projects-section-label {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}
.projects-other-toggle { display: flex; align-items: center; gap: 0.8rem; flex-shrink: 0; }
.projects-other-count {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  padding: 0.22rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 20px;
  transition: all 0.3s var(--ease-out);
}
.projects-other-dropdown:hover .projects-other-count {
  border-color: var(--accent);
  color: var(--accent);
}
.projects-other-header .edu-toggle-icon {
  transition: transform 0.6s var(--ease-out), color 0.3s var(--ease-out);
}
.projects-other-dropdown.expanded .projects-other-header .edu-toggle-icon {
  transform: rotate(180deg);
  color: var(--accent);
}
.projects-other-content {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height 0.8s var(--ease-out), opacity 0.5s ease;
}
.projects-other-dropdown.expanded .projects-other-content {
  max-height: 2400px;
  opacity: 1;
  overflow: visible;
}
.projects-other-content > .projects-grid { padding: 0 1.8rem 1.8rem; }

/* The "ANTI-3-COL" rule: use zig-zag-friendly 2-col with asymmetry handled per card */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}

.proj-card {
  --spot-x: 50%;
  --spot-y: 50%;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.8rem;
  transition: border-color 0.35s var(--ease-out), transform 0.35s var(--ease-out);
  position: relative;
  overflow: hidden;
}
.proj-card::before {
  /* Spotlight border: tracks mouse via CSS custom properties */
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: radial-gradient(220px circle at var(--spot-x) var(--spot-y),
    color-mix(in srgb, var(--accent) 50%, transparent), transparent 60%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
          mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.4s var(--ease-out);
  pointer-events: none;
}
.proj-card:hover::before { opacity: 1; }
.proj-card:hover {
  border-color: var(--border-strong);
  transform: translateY(-3px);
}

.proj-num {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--accent);
  letter-spacing: 0.14em;
  margin-bottom: 1rem;
}
.proj-title {
  font-family: var(--serif);
  font-size: 1.5rem;
  font-weight: 400;
  margin-bottom: 0.6rem;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}
.proj-desc {
  color: var(--text-secondary);
  font-size: 0.96rem;
  margin-bottom: 1.3rem;
  line-height: 1.75;
}
.proj-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.tag {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  padding: 0.28rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 3px;
  letter-spacing: 0.05em;
  transition: all 0.25s var(--ease-out);
}
.proj-card:hover .tag {
  border-color: var(--border-strong);
  color: var(--text-secondary);
}

.proj-links {
  display: flex;
  gap: 1.4rem;
  margin-top: 1.2rem;
  flex-wrap: wrap;
}
.proj-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--text-secondary);
  letter-spacing: 0.04em;
  transition: color 0.25s var(--ease-out), transform 0.25s var(--ease-out);
  padding: 0.35rem 0;
  border-bottom: 1px solid transparent;
}
.proj-link.primary { color: var(--accent); border-bottom-color: var(--accent-soft); }
.proj-link:hover { color: var(--accent); transform: translateX(3px); }

/* ===== CERTIFICATES ===== */
.cert-list { display: flex; flex-direction: column; gap: 0; border-top: 1px solid var(--rule); }
.cert-item {
  display: flex;
  align-items: center;
  gap: 1.4rem;
  padding: 1.3rem 0.5rem;
  background: transparent;
  border: none;
  border-bottom: 1px solid var(--rule);
  border-radius: 0;
  transition: background 0.3s var(--ease-out), padding-left 0.3s var(--ease-out);
  position: relative;
}
.cert-item::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 2px;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.4s var(--ease-out);
}
.cert-item:hover { padding-left: 1.5rem; background: var(--accent-glow); }
.cert-item:hover::before { transform: scaleY(1); }
.cert-icon {
  width: 38px; height: 38px;
  border-radius: 50%;
  background: var(--accent-glow);
  border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.cert-icon svg {
  width: 17px; height: 17px;
  stroke: var(--accent);
  fill: none;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.cert-links {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  flex-shrink: 0;
  margin-left: auto;
}
.cert-verify-link {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  padding: 0.22rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 3px;
  transition: all 0.3s var(--ease-out);
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}
.cert-verify-link svg { stroke: currentColor; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.cert-verify-link:hover { color: var(--accent); border-color: var(--accent); background: var(--accent-glow); }
.cert-info { flex: 1; }
.cert-name {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  margin-bottom: 0.15rem;
  color: var(--text-primary);
}
.cert-issuer { font-size: 0.9rem; color: var(--text-secondary); font-family: var(--mono); letter-spacing: 0.02em; }
.cert-year { font-family: var(--mono); font-size: 0.78rem; color: var(--text-muted); letter-spacing: 0.06em; }

/* ===== CONTACT ===== */
.contact-layout {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 4rem;
  align-items: start;
}
.contact-text h3 {
  font-family: var(--serif);
  font-size: 1.7rem;
  font-weight: 400;
  letter-spacing: -0.01em;
  margin-bottom: 0.7rem;
  color: var(--text-primary);
}
.contact-text p {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 50ch;
  margin-bottom: 1.4rem;
  line-height: 1.75;
}
.contact-links { display: flex; flex-direction: column; gap: 0.5rem; }
.contact-link {
  display: flex;
  align-items: center;
  gap: 1rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  transition: color 0.3s var(--ease-out), border-color 0.3s var(--ease-out), padding-left 0.3s var(--ease-out);
  padding: 0.75rem 1.1rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-elev);
}
.contact-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  padding-left: 1.4rem;
}
.contact-link svg {
  width: 17px; height: 17px;
  stroke: var(--text-muted);
  fill: none;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  flex-shrink: 0;
  transition: stroke 0.3s var(--ease-out);
}
.contact-link:hover svg { stroke: var(--accent); }
.contact-creative { display: flex; flex-direction: column; gap: 1.2rem; }
.contact-code-block {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}
.contact-code-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.55rem 1.2rem;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--rule);
}
.contact-code-dots { display: flex; gap: 6px; }
.dot-red, .dot-yellow, .dot-green {
  width: 9px; height: 9px;
  border-radius: 50%;
}
.dot-red { background: #E06C5C; }
.dot-yellow { background: #E2B047; }
.dot-green { background: #4DA37D; }
.contact-code-filename {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}
.contact-code {
  font-family: var(--mono);
  font-size: 0.78rem;
  line-height: 1.7;
  padding: 1.1rem 1.5rem;
  color: var(--text-secondary);
  white-space: pre;
  overflow-x: auto;
}
.code-keyword { color: var(--accent); }
.code-class { color: #6F9DD0; font-weight: 500; }
.code-func { color: #C9A65A; }
.code-param { color: var(--text-secondary); }
.code-string { color: var(--accent-soft); }
.code-bool { color: var(--accent); }
.code-comment { color: var(--text-muted); font-style: italic; }
.code-num { color: #C9A65A; }
[data-theme="light"] .code-class { color: #295E94; }
[data-theme="light"] .code-func { color: #8C6A1F; }
[data-theme="light"] .code-num { color: #8C6A1F; }

.contact-stats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.6rem;
}
.contact-stat {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.9rem;
  text-align: center;
  transition: border-color 0.3s var(--ease-out), transform 0.3s var(--ease-out);
}
.contact-stat:hover { border-color: var(--accent); transform: translateY(-2px); }
.contact-stat-num {
  font-family: var(--serif);
  font-size: 1.7rem;
  font-style: italic;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 0.3rem;
}
.contact-stat-label {
  font-family: var(--mono);
  font-size: 0.62rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* ===== FOOTER ===== */
.footer {
  position: relative;
  z-index: 2;
  padding: 2.5rem 3rem;
  border-top: 1px solid var(--rule);
  text-align: center;
}
.footer p {
  font-family: var(--mono);
  font-size: 0.66rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
}

/* ===== REVEAL ===== */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
  will-change: opacity, transform;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== VIEW TRANSITIONS ===== */
@supports (view-transition-name: a) {
  ::view-transition-old(root),
  ::view-transition-new(root) {
    animation-duration: 0.45s;
    animation-timing-function: cubic-bezier(0.16, 1, 0.3, 1);
  }
  ::view-transition-old(root) {
    animation-name: fadeOutSlide;
  }
  ::view-transition-new(root) {
    animation-name: fadeInSlide;
  }
}
@keyframes fadeOutSlide {
  to { opacity: 0; transform: translateY(-12px); }
}
@keyframes fadeInSlide {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== RESPONSIVE ===== */
@media (max-width: 900px) {
  .top-nav { padding: 1rem 1.4rem; }
  .top-nav-links { gap: 1rem; }
  .top-nav-links a { font-size: 0.6rem; }
  .page-content { padding: 6rem 1.4rem 3rem; }
  .about-content, .projects-grid, .contact-layout { grid-template-columns: 1fr; gap: 2.5rem; }
  .contact-creative { display: none; }
  .contact-stats-row { grid-template-columns: 1fr 1fr; }
  .tl-item { grid-template-columns: 1fr; gap: 0.3rem; padding: 1.6rem 0; }
  .tl-item:hover { padding-left: 0.8rem; }
  .footer { padding: 1.8rem 1.4rem; }
  .scroll-rail { display: none; }
  .theme-toggle { top: 1rem; right: 1rem; width: 28px; height: 50px; }
  [data-theme="light"] .theme-toggle-thumb { transform: translateY(22px); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  body::before { display: none; }
}