/* ─────────────────────────────────────────
   base.css — Reset, body, global elements
───────────────────────────────────────── */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background var(--transition), color var(--transition);
}

/* ── Scrollbar ── */
::-webkit-scrollbar         { width: 5px; }
::-webkit-scrollbar-track   { background: transparent; }
::-webkit-scrollbar-thumb   { background: var(--border2); border-radius: 10px; }

/* ── Section shared ── */
section { padding: 7rem 2rem; }

.container {
  max-width: 1100px;
  margin: 0 auto;
}

/* ── Section labels ── */
.section-tag {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 1rem;
  letter-spacing: -0.5px;
}

.section-sub {
  color: var(--text2);
  font-size: 1rem;
  max-width: 540px;
  margin-bottom: 3rem;
  line-height: 1.7;
}

/* ── Scroll Reveal ── */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Buttons ── */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0.85rem 2rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 10px;
  font-family: var(--sans);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition);
  box-shadow: 0 0 30px rgba(79,142,255,0.35);
}
.btn-primary:hover {
  background: #6fa0ff;
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(79,142,255,0.5);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0.85rem 1.75rem;
  border: 1px solid var(--border2);
  color: var(--text2);
  border-radius: 10px;
  font-family: var(--sans);
  font-size: 0.92rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  background: var(--surface);
  transition: all var(--transition);
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(79,142,255,0.07);
}

/* ── Difficulty badges ── */
.difficulty {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: var(--mono);
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: 3px 10px;
  border-radius: 100px;
}
.difficulty.beginner     { background: rgba(6,214,160,0.12);  color: var(--accent3); }
.difficulty.intermediate { background: rgba(255,214,10,0.12); color: var(--accent5); }
.difficulty.advanced     { background: rgba(247,37,133,0.12); color: var(--accent4); }

/* ── Tags ── */
.tag {
  font-family: var(--mono);
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  padding: 3px 9px;
  border-radius: 6px;
  background: var(--surface2);
  color: var(--text3);
}

/* ── Footer ── */
footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 2rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text3);
  font-family: var(--mono);
}
footer strong { color: var(--accent); }