:root {
  color-scheme: light;
  --bg: #eef1ea;
  --surface: #fbfcf8;
  --ink: #18231b;
  --muted: #667069;
  --line: rgba(24, 35, 27, 0.14);
  --green: #31553a;
  --gold: #a67b2e;
  font-family: "DM Sans", system-ui, sans-serif;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #101511;
  --surface: #1b241d;
  --ink: #f1f4ef;
  --muted: #a9b3ab;
  --line: rgba(241, 244, 239, 0.13);
  --green: #90bc96;
  --gold: #d6b163;
}

* { box-sizing: border-box; }
html { background: var(--bg); }
body { min-width: 320px; margin: 0; background: var(--bg); color: var(--ink); }
.skip-link { position: fixed; top: 8px; left: 8px; z-index: 100; transform: translateY(-160%); border-radius: 8px; background: var(--ink); color: var(--bg); padding: 10px 14px; }
.skip-link:focus { transform: translateY(0); }

main { width: min(1000px, calc(100% - 32px)); margin: 0 auto; padding: clamp(32px, 6vw, 72px) 0 54px; }
.page-heading { display: grid; gap: 10px; margin-bottom: 24px; }
.page-heading a { width: max-content; color: var(--green); font-size: 0.82rem; font-weight: 800; text-decoration: none; }
.page-heading h1 { margin: 0; font: 500 clamp(3rem, 8vw, 6rem)/0.9 "Newsreader", serif; letter-spacing: -0.05em; }

.book-list { display: grid; gap: 10px; margin: 0; }
.book-card { display: grid; min-width: 0; min-height: 132px; grid-template-columns: 88px minmax(0, 1fr); align-items: center; overflow: hidden; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); }
.book-card img { width: 88px; height: 100%; min-height: 132px; object-fit: contain; background: #fff; }
.book-card > div { padding: 20px 24px; }
.book-list h2 { margin: 0; font-size: clamp(1.2rem, 3vw, 1.8rem); letter-spacing: -0.035em; }
.book-list p { margin: 5px 0 0; color: var(--muted); font-size: 0.9rem; }
.book-list .book-meta { color: var(--gold); font-size: 0.76rem; font-weight: 700; }
.book-list .book-summary { max-width: 720px; margin-top: 10px; line-height: 1.5; }
.cover-credit { margin: 18px 0 0; text-align: right; }
.cover-credit a { color: var(--muted); font-size: 0.7rem; text-decoration: none; }

@media (max-width: 760px) {
  main { width: calc(100% - 24px); padding-top: 30px; }
  .book-card { min-height: 108px; grid-template-columns: 72px minmax(0, 1fr); border-radius: 14px; }
  .book-card img { width: 72px; min-height: 108px; }
  .book-card > div { padding: 14px 16px; }
  .book-list h2 { font-size: clamp(1rem, 4.3vw, 1.3rem); }
  .book-list .book-summary { font-size: 0.8rem; }
}

/* Universal button-border contract: every enabled button renders a visible 1px border. */
button:not(:disabled) {
  border-style: solid !important;
  border-width: 1px !important;
}