/*
 * base.css
 * ─────────────────────────────────────────────────────────────
 * Global reset, body defaults, shared typography utilities,
 * keyframe animations, and scroll-reveal classes.
 *
 * Applies to the whole site — nothing section-specific here.
 * ─────────────────────────────────────────────────────────────
 */

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

/* ── Base ── */
html { scroll-behavior: smooth; }

body {
  background: var(--off-white);
  color: var(--ink);
  font-family: 'DM Sans', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  overflow-x: hidden;
}

/* ── Shared section utilities ── */
section { padding: 6rem 4rem; }

.s-label {
  font-family: 'DM Mono', monospace;
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--blue);
  display: block;
  margin-bottom: 0.75rem;
}

.s-title {
  font-family: 'Playfair Display', serif;
  font-size: clamp(2rem, 3.5vw, 3rem);
  font-weight: 900;
  line-height: 1.1;
}

/* Accessible accent: darker on light backgrounds */
.s-title em { font-style: italic; color: #3D5FA8; }

/* Lighter accent on dark section backgrounds (contrast verified) */
#superpower .s-title em,
#experience .s-title em,
#research .s-title em,
.skills-left .s-title em { color: #7B9FDE; }

.s-sub {
  font-size: 0.98rem;
  color: var(--slate);
  font-weight: 300;
  line-height: 1.7;
  max-width: 480px;
  margin-top: 0.75rem;
}

.s-rule {
  width: 50px;
  height: 3px;
  background: var(--blue);
  margin-top: 1.25rem;
  border-radius: 2px;
}
.s-rule.light { background: var(--blue-light); }

/* ── Shared buttons ── */
.btn-primary {
  display: inline-block;
  background: var(--blue);
  color: var(--white);
  padding: 0.8rem 1.8rem;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  border-radius: 4px;
  transition: background 0.2s;
}
.btn-primary:hover { background: var(--ink); }

.btn-outline {
  display: inline-block;
  border: 1.5px solid var(--silver-dark);
  color: var(--ink);
  padding: 0.8rem 1.8rem;
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  border-radius: 4px;
  transition: all 0.2s;
}
.btn-outline:hover {
  border-color: var(--blue);
  color: var(--blue);
  background: var(--blue-dim);
}

/* ── Keyframe animations ── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes ticker {
  from { transform: translateX(0); }
  to   { transform: translateX(-50%); }
}

@keyframes lineGrow {
  from { width: 0; }
  to   { width: 100%; }
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* ── Scroll-reveal ── */
/* Elements with .sr are invisible until they enter the viewport.
   JavaScript in scroll-reveal.js adds .visible via IntersectionObserver. */
.sr {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.sr.visible  { opacity: 1; transform: translateY(0); }
.sr-d1 { transition-delay: 0.1s; }
.sr-d2 { transition-delay: 0.2s; }
.sr-d3 { transition-delay: 0.3s; }