:root {
  --ink: #1e2320;
  --muted: #69716d;
  --paper: #f6f1e7;
  --panel: #fffaf0;
  --line: #d8ccb6;
  --accent: #ad3d2b;
  --accent-dark: #7d2c20;
  --green: #225b52;
  --shadow: 0 18px 50px rgba(40, 33, 22, 0.16);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(173, 61, 43, 0.18), transparent 30rem),
    linear-gradient(135deg, #efe4cf 0%, #f8f3e9 45%, #dbe7df 100%);
  font-family: Cambria, Constantia, "Palatino Linotype", Georgia, serif;
}

button,
input,
audio {
  font: inherit;
}

.shell {
  display: grid;
  grid-template-columns: minmax(17rem, 24rem) minmax(0, 1fr);
  gap: 1.25rem;
  min-height: 100vh;
  padding: 1.25rem;
}

.library,
.reader {
  border: 1px solid rgba(125, 44, 32, 0.18);
  background: rgba(255, 250, 240, 0.82);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.library {
  display: flex;
  flex-direction: column;
  height: calc(100vh - 2.5rem);
  min-height: 0;
  padding: 1rem;
}

.brand {
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}

.kicker {
  margin: 0 0 0.25rem;
  color: var(--accent-dark);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0;
  letter-spacing: 0;
  line-height: 1.08;
}

h1 {
  font-size: clamp(1.7rem, 4vw, 2.8rem);
}

h2 {
  font-size: clamp(2.1rem, 5vw, 4.8rem);
}

h3 {
  color: var(--green);
  font-size: 1.15rem;
}

.search-label {
  margin-top: 1rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.search {
  width: 100%;
  margin: 0.35rem 0 0.8rem;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--ink);
  background: #fffdf8;
}

.track-list {
  display: grid;
  flex: 1;
  gap: 1rem;
  min-height: 0;
  margin: 0;
  padding: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
}

.chapter-group {
  display: grid;
  gap: 0.35rem;
}

.chapter-title {
  padding: 0 0.35rem 0.35rem;
  border-bottom: 1px solid var(--line);
  color: var(--green);
  font-size: 0.95rem;
  line-height: 1.4;
}

.chapter-lessons {
  display: grid;
  gap: 0.2rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.track-button {
  width: 100%;
  min-height: 2.7rem;
  padding: 0.55rem 0.75rem;
  border: 1px solid transparent;
  border-radius: 6px;
  color: var(--ink);
  background: transparent;
  text-align: left;
  cursor: pointer;
}

.track-button:hover,
.track-button.is-active {
  border-color: rgba(173, 61, 43, 0.28);
  background: rgba(173, 61, 43, 0.1);
}

.reader {
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr);
  gap: 1rem;
  padding: clamp(1rem, 4vw, 2rem);
}

.reader-header {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  justify-content: space-between;
}

.nav-buttons {
  display: flex;
  gap: 0.5rem;
  flex: 0 0 auto;
}

.nav-buttons button {
  min-width: 4.5rem;
  min-height: 2.5rem;
  border: 1px solid var(--accent-dark);
  border-radius: 6px;
  color: #fffaf0;
  background: var(--accent-dark);
  cursor: pointer;
}

.nav-buttons button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.audio {
  width: 100%;
}

.transcript-panel {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: 0.8rem;
  min-height: 0;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 253, 248, 0.72);
}

.transcript {
  min-height: 0;
  margin: 0;
  overflow: auto;
  white-space: pre-wrap;
  color: #2b302d;
  font-family: Cambria, Constantia, "Palatino Linotype", Georgia, serif;
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  line-height: 1.7;
}

.empty {
  padding: 1rem;
  color: var(--muted);
}

@media (max-width: 800px) {
  .shell {
    grid-template-columns: 1fr;
    padding: 0.75rem;
  }

  .library {
    height: auto;
    min-height: auto;
    max-height: 45vh;
  }

  .reader-header {
    flex-direction: column;
  }
}