body[data-scheme="d"] {
  --ivory: #f6f1e6;
  --brown: #5a3a29;
  --copper: #b07a3b;
  --mist: #6e8ca0;
  --ink: #222120;
  background:
    radial-gradient(circle at 18% 0%, rgba(176, 122, 59, 0.12), transparent 30%),
    var(--ivory);
  color: var(--ink);
}

body[data-scheme="d"] .serif {
  font-family: "Songti SC", "STSong", "Noto Serif SC", "SimSun", serif;
}

body[data-scheme="d"] .site-header,
body[data-scheme="d"] .site-footer {
  border-color: #d8ccb6;
}

body[data-scheme="d"] .primary-btn {
  background: var(--brown);
  color: #f8f1e6;
  border-color: var(--brown);
}

body[data-scheme="d"] h1 {
  margin: 16px 0 8px;
  font-size: clamp(34px, 5vw, 56px);
  line-height: 1.15;
  font-weight: 800;
}

body[data-scheme="d"] .task {
  margin: 0 0 8px;
  max-width: 680px;
}

body[data-scheme="d"] .assume {
  margin: 0 0 16px;
  font-size: 13px;
  letter-spacing: 0.04em;
}

body[data-scheme="d"] .stage {
  display: grid;
  grid-template-columns: minmax(0, 1.62fr) minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

body[data-scheme="d"] .canal-wrap {
  height: 390px;
  background: #f4ebda;
  border: 1px solid #d8ccb6;
}

body[data-scheme="d"] .canal-wrap svg {
  display: block;
  width: 100%;
  height: 100%;
}

body[data-scheme="d"] .canal-wrap .canal-mobile {
  display: none;
}

body[data-scheme="d"] .control-col {
  display: grid;
  gap: 12px;
}

body[data-scheme="d"] label {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

body[data-scheme="d"] input[type="range"],
body[data-scheme="d"] select {
  width: 100%;
  min-height: 44px;
}

body[data-scheme="d"] .totals {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  font-size: 13px;
  line-height: 1.5;
  font-variant-numeric: tabular-nums;
}

body[data-scheme="d"] .year-now {
  display: none;
}

body[data-scheme="d"] input[type="range"] {
  accent-color: var(--copper);
}

body[data-scheme="d"] select {
  border: 1px solid #c4a06a;
  padding: 6px 10px;
  color: var(--brown);
  background: var(--ivory);
}

body[data-scheme="d"] .totals b {
  display: block;
  font-size: 32px;
  line-height: 1.15;
  font-weight: 600;
  color: var(--brown);
}

body[data-scheme="d"] .mode-switch {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

body[data-scheme="d"] .mode-switch button[aria-pressed="true"] {
  background: var(--copper);
  color: #fff8ee;
  border-color: var(--copper);
}

body[data-scheme="d"] .canal-wrap[data-mode="sees"] .end-pay {
  font-weight: 700;
}

body[data-scheme="d"] .canal-wrap[data-mode="midamerican"] .end-retain {
  font-weight: 700;
}

body[data-scheme="d"] .flow-note {
  min-height: 4.5em;
  margin: 0;
  font-size: 16px;
}

body[data-scheme="d"] .history-block,
body[data-scheme="d"] .formula {
  margin: 20px 0;
  max-width: 680px;
}

body[data-scheme="d"] summary {
  cursor: pointer;
  min-height: 44px;
}

body[data-scheme="d"] .quiz-block button.is-correct {
  background: #e7dcc8;
}

body[data-scheme="d"] .quiz-block button.is-miss {
  background: #f0d4cc;
}

@media (max-width: 900px) {
  body[data-scheme="d"] .stage {
    grid-template-columns: 1fr;
  }

  body[data-scheme="d"] .control-col {
    display: contents;
  }

  body[data-scheme="d"] .stage {
    gap: 12px;
  }

  body[data-scheme="d"] .control-col > label {
    order: -3;
  }

  body[data-scheme="d"] .canal-col {
    order: -2;
  }

  body[data-scheme="d"] .totals {
    order: -1;
  }

  body[data-scheme="d"] .canal-wrap .canal-desktop {
    display: none;
  }

  body[data-scheme="d"] .canal-wrap .canal-mobile {
    display: block;
  }

  body[data-scheme="d"] .canal-wrap {
    height: 280px;
  }

  body[data-scheme="d"] .totals b {
    font-size: 22px;
  }
}

@media (max-width: 390px) {
  body[data-scheme="d"] h1 {
    font-size: 36px;
  }

  body[data-scheme="d"] .canal-wrap {
    height: 270px;
  }
}

@media (max-width: 320px) {
  body[data-scheme="d"] h1 {
    font-size: 34px;
  }

  body[data-scheme="d"] .canal-wrap {
    height: 260px;
  }

  body[data-scheme="d"] .totals b {
    font-size: 20px;
  }
}