/* Fretwork: mobile-first, dark, one stylesheet. Propshaft serves it as-is. */

:root {
  color-scheme: dark;
  --bg: #111318;
  --surface: #1a1d25;
  --surface-hover: #222633;
  --border: #2b303d;
  --text: #f0f0f0;
  --muted: #9ca3af;
  --accent: #a5b4fc;
  --accent-soft: rgba(165, 180, 252, 0.1);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 100%;
  line-height: 1.6;
}

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

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
}

a { color: var(--accent); }

:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.site-header,
main {
  width: 100%;
  max-width: 40rem;
  margin: 0 auto;
  padding-inline: 1rem;
}

.site-header { padding-block: 1rem 0; }

.logo {
  display: inline-block;
  padding-block: 0.5rem;
  color: var(--text);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  text-decoration: none;
}
.logo span { color: var(--accent); }

main { padding-block: 1rem 4rem; }

h1 {
  margin: 0.5rem 0 0.5rem;
  font-size: clamp(2rem, 7vw, 3rem);
  line-height: 1.1;
  letter-spacing: -0.04em;
}

h2 {
  margin: 0 0 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.meta { margin: 0 0 2rem; color: var(--muted); }

/* Library list */

.exercises {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.75rem;
}

.exercise a {
  display: block;
  min-height: 3.5rem;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text);
  text-decoration: none;
}
.exercise a:hover,
.exercise a:active { background: var(--surface-hover); border-color: var(--accent); }

.exercise strong { display: block; font-size: 1.15rem; line-height: 1.3; }
.exercise span { display: block; margin-top: 0.25rem; color: var(--muted); }
.exercise small { display: block; margin-top: 0.5rem; color: var(--accent); font-size: 0.85rem; }

/* Exercise page */

.back {
  display: inline-block;
  padding-block: 0.75rem;
  text-decoration: none;
}

section { margin-block: 2rem; }

section p {
  margin: 0 0 1rem;
  font-size: 1.15rem;
  line-height: 1.7;
  max-width: 36rem;
}

.challenge {
  padding: 1rem 1.25rem;
  background: var(--accent-soft);
  border-left: 4px solid var(--accent);
  border-radius: 0 12px 12px 0;
}
.challenge p:last-child { margin-bottom: 0; }

.tips p { color: var(--muted); }

@media (min-width: 40rem) {
  .site-header { padding-block-start: 2rem; }
  main { padding-block-start: 2rem; }
}

@media (prefers-reduced-motion: no-preference) {
  .exercise a { transition: background 0.15s, border-color 0.15s; }
}