/* =========================================================
   Hội Ngộ 20 Năm — Phạm Phú Thứ 2006–2026
   Vintage Yearbook aesthetic
   ========================================================= */

:root {
  --paper: #f4ecd8;
  --paper-dark: #e8dcc0;
  --ink: #2a2420;
  --ink-soft: #5c4a3a;
  --ink-faint: #8b7355;
  --accent: #b8472a;
  --accent-dark: #8a3420;
  --moss: #5c6b4a;
  --rule: #2a2420;
  --shadow: 0 2px 0 rgba(42, 36, 32, 0.08);

  --font-display: "Playfair Display", "Times New Roman", serif;
  --font-serif: "EB Garamond", "Georgia", serif;
  --font-mono: "JetBrains Mono", "Courier New", monospace;

  --page-max: 1280px;
  --gutter: 48px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-serif);
  background: var(--paper);
  color: var(--ink);
  font-size: 18px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Paper grain overlay */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1000;
  opacity: 0.35;
  mix-blend-mode: multiply;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(139, 115, 85, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(139, 115, 85, 0.06) 0%, transparent 50%),
    url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.3  0 0 0 0 0.25  0 0 0 0 0.2  0 0 0 0.4 0'/></filter><rect width='200' height='200' filter='url(%23n)' opacity='0.5'/></svg>");
}

/* Typography */
.display { font-family: var(--font-display); font-weight: 900; letter-spacing: -0.02em; line-height: 0.95; }
.mono { font-family: var(--font-mono); letter-spacing: 0.05em; }
.caps { text-transform: uppercase; letter-spacing: 0.15em; font-size: 0.75em; }
.italic { font-style: italic; }

h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; line-height: 1.05; }

/* Page shell (yearbook frame) */
.page {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
  position: relative;
}

/* Ruled header bar like book index */
.index-bar {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  border-top: 2px solid var(--ink);
  border-bottom: 0.5px solid var(--ink);
  padding: 10px 0 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.section-number {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.25em;
  color: var(--accent);
  margin-bottom: 12px;
  display: inline-block;
}

.section-title {
  font-size: clamp(42px, 6vw, 84px);
  margin-bottom: 16px;
  letter-spacing: -0.03em;
}

.section-title em {
  font-style: italic;
  color: var(--accent);
  font-weight: 500;
}

.section-dek {
  font-family: var(--font-serif);
  font-size: 20px;
  font-style: italic;
  color: var(--ink-soft);
  max-width: 640px;
  margin-bottom: 48px;
}

/* Horizontal rule with mark */
.rule {
  border: 0;
  border-top: 0.5px solid var(--ink);
  margin: 24px 0;
}

.rule-thick {
  border: 0;
  border-top: 2px solid var(--ink);
  border-bottom: 0.5px solid var(--ink);
  padding-bottom: 4px;
  margin: 24px 0;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 14px 28px;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  cursor: pointer;
  border: 2px solid var(--ink);
  text-decoration: none;
  transition: all 0.2s ease;
}

.btn:hover {
  background: var(--accent);
  border-color: var(--accent);
}

.btn-accent {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

.btn-accent:hover { background: var(--accent-dark); border-color: var(--accent-dark); }

.btn-ghost {
  background: transparent;
  color: var(--ink);
}

.btn-ghost:hover { background: var(--ink); color: var(--paper); }

/* Placeholder image */
.placeholder {
  background-color: var(--paper-dark);
  background-image: repeating-linear-gradient(
    45deg,
    transparent,
    transparent 8px,
    rgba(42, 36, 32, 0.06) 8px,
    rgba(42, 36, 32, 0.06) 9px
  );
  border: 0.5px solid var(--ink-faint);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--ink-faint);
  text-align: center;
  padding: 12px;
  position: relative;
}

.placeholder::before {
  content: "";
  position: absolute;
  inset: 6px;
  border: 0.5px dashed var(--ink-faint);
  pointer-events: none;
}

/* Form elements */
input[type="text"], input[type="email"], input[type="tel"], input[type="number"], textarea, select {
  width: 100%;
  background: transparent;
  border: none;
  border-bottom: 1px solid var(--ink);
  padding: 10px 0;
  font-family: var(--font-serif);
  font-size: 18px;
  color: var(--ink);
  outline: none;
  transition: border-color 0.2s;
}

input:focus, textarea:focus, select:focus {
  border-bottom-color: var(--accent);
  border-bottom-width: 2px;
}

label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-soft);
  display: block;
  margin-bottom: 4px;
}

textarea { resize: vertical; min-height: 80px; }

/* Scroll reveal */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
.reveal.in {
  opacity: 1;
  transform: translateY(0);
}

/* Tweaks panel */
.tweaks-panel {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 280px;
  background: var(--paper);
  border: 1.5px solid var(--ink);
  padding: 20px;
  z-index: 500;
  box-shadow: 4px 4px 0 var(--ink);
  font-family: var(--font-serif);
}

.tweaks-panel h3 {
  font-family: var(--font-display);
  font-size: 18px;
  margin-bottom: 4px;
}

.tweaks-panel .tweak-row {
  margin-top: 16px;
}

.tweaks-panel .swatches {
  display: flex;
  gap: 8px;
  margin-top: 6px;
}

.tweaks-panel .swatch {
  width: 28px;
  height: 28px;
  border: 1.5px solid var(--ink);
  cursor: pointer;
  transition: transform 0.15s;
}
.tweaks-panel .swatch:hover { transform: scale(1.1); }
.tweaks-panel .swatch.on { outline: 2px solid var(--ink); outline-offset: 2px; }

.tweaks-panel select {
  border: 1px solid var(--ink);
  padding: 6px 8px;
  font-size: 14px;
  margin-top: 4px;
}

/* Ornaments */
.ornament {
  text-align: center;
  font-family: var(--font-display);
  font-size: 20px;
  color: var(--ink-faint);
  letter-spacing: 1em;
  padding: 24px 0;
}

/* Accent pill */
.pill {
  display: inline-block;
  background: var(--accent);
  color: var(--paper);
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.2em;
}

/* Responsive */
@media (max-width: 768px) {
  :root { --gutter: 20px; }
  body { font-size: 16px; }
}