:root {
  color-scheme: light;
  --bg: #f6f0e5;
  --surface: #fffdf8;
  --surface-alt: #f3ead8;
  --text: #2c2216;
  --muted: #6a5843;
  --accent: #8b5e34;
  --accent-dark: #6f4520;
  --border: #dccbb3;
  --shadow: 0 18px 42px rgba(71, 50, 24, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, #fbf8f1 0%, var(--bg) 100%);
}

.page {
  max-width: 1040px;
  margin: 0 auto;
  padding: 64px 24px 80px;
}

.hero,
.details,
.entry-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow);
}

.hero,
.details {
  padding: 40px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2 {
  margin: 0;
}

h1 {
  font-size: clamp(2.3rem, 4vw, 4rem);
  line-height: 1.05;
}

.lead,
.section-copy,
.empty-state {
  color: var(--muted);
  line-height: 1.7;
}

.lead {
  max-width: 760px;
  margin: 20px 0 0;
  font-size: 1.1rem;
}

.details {
  margin-top: 28px;
}

.viewer-controls {
  display: grid;
  grid-template-columns: auto minmax(180px, 240px) auto;
  gap: 16px;
  align-items: end;
  margin-bottom: 24px;
}

.nav-button,
.date-picker input {
  border: 1px solid var(--border);
  border-radius: 14px;
  font: inherit;
}

.nav-button {
  padding: 14px 18px;
  background: var(--surface-alt);
  color: var(--text);
  cursor: pointer;
}

.nav-button:hover,
.nav-button:focus-visible,
.date-picker input:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.date-picker {
  display: grid;
  gap: 8px;
}

.date-picker span {
  color: var(--accent-dark);
  font-size: 0.9rem;
  font-weight: 700;
}

.date-picker input {
  width: 100%;
  padding: 13px 14px;
  background: var(--surface);
}

.entry-card {
  padding: 24px;
}

.entry-date {
  margin: 0 0 18px;
  color: var(--accent-dark);
  font-size: 0.95rem;
  font-weight: 700;
}

.reference-card {
  display: block;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: var(--surface-alt);
  color: inherit;
  text-decoration: none;
}

.reference-card:hover,
.reference-card:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.reference-label {
  display: block;
  margin-bottom: 8px;
  color: var(--accent-dark);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.reference-card strong {
  font-size: 1.1rem;
}

.entry-thought {
  margin: 0 0 24px;
  padding: 20px 22px;
  border-left: 4px solid var(--accent);
  border-radius: 18px;
  background: var(--surface-alt);
  color: var(--text);
  font-size: 1.08rem;
  line-height: 1.8;
  font-weight: 600;
}

.empty-state {
  margin: 0;
  padding: 24px;
  border: 1px dashed var(--border);
  border-radius: 18px;
  background: var(--surface-alt);
}

.iframe-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.iframe-card {
  display: grid;
  gap: 12px;
}

.study-frame {
  width: 100%;
  min-height: 640px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #ffffff;
}

.iframe-reference {
  height: 100%;
}

@media (max-width: 640px) {
  .page {
    padding: 24px 16px 48px;
  }

  .hero,
  .details {
    padding: 24px;
  }

  .entry-card {
    padding: 20px;
  }

  .viewer-controls {
    grid-template-columns: 1fr;
    align-items: stretch;
  }

  .study-frame {
    min-height: 480px;
  }
}