:root {
    --bg: #f7f9fb;
    --surface: #ffffff;
    --on-surface: #191c1e;
    --on-surface-variant: #434655;
    --outline-variant: #c3c6d7;
    --primary: #004ac6;
    --cell-height: 60vh;
  }
  @media (prefers-color-scheme: dark) {
    :root {
      --bg: #111417;
      --surface: #191c1e;
      --on-surface: #e2e2e5;
      --on-surface-variant: #c3c6d7;
      --outline-variant: #43464f;
      --primary: #b4c5ff;
    }
  }

  * { box-sizing: border-box; }

  body {
    margin: 0;
    background: var(--bg);
    color: var(--on-surface);
    font: 16px/1.5 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    -webkit-text-size-adjust: 100%;
  }

  #root {
    max-width: 1100px;
    margin: 0 auto;
    padding: 16px 16px 48px;
  }

  .header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 12px;
  }
  .header h1 {
    font-size: 22px;
    font-weight: 600;
    margin: 0;
    color: var(--primary);
  }
  .open-app {
    font-size: 13px;
    color: var(--primary);
    text-decoration: none;
    border: 1px solid var(--outline-variant);
    border-radius: 999px;
    padding: 6px 14px;
    white-space: nowrap;
  }

  .grid { display: grid; gap: 2px; }
  .cell {
    position: relative;
    height: var(--cell-height);
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 8px;
    overflow: hidden;
  }
  .cell canvas {
    display: block;
    width: 100%;
    height: 100%;
    touch-action: none;
    cursor: grab;
  }
  .cell canvas:active { cursor: grabbing; }

  .badge {
    position: absolute;
    top: 8px;
    left: 8px;
    font-size: 11px;
    font-weight: 600;
    padding: 3px 9px;
    border-radius: 999px;
    background: var(--bg);
    color: var(--on-surface-variant);
    border: 1px solid var(--outline-variant);
    pointer-events: none;
  }

  .legend, .sliders {
    margin-top: 20px;
    padding: 12px 16px;
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 8px;
  }
  .legend h2, .sliders h2 {
    font-size: 11px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--on-surface-variant);
    margin: 0 0 10px;
    font-weight: 600;
  }
  .legend-row {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 5px 0;
  }
  .swatch {
    width: 26px;
    border-radius: 3px;
    flex: none;
  }
  .legend-row code {
    font-family: ui-monospace, SFMono-Regular, "Roboto Mono", Menlo, monospace;
    font-size: 15px;
  }
  /* Kök ders kitabındaki gibi: üst çizgi içindeki ifadenin tamamını örtüyor */
  .legend-row .root {
    display: inline-flex;
    align-items: flex-end;
    margin: 0 1px;
  }
  .legend-row .root-index {
    font-size: 10px;
    line-height: 1;
    align-self: flex-start;
    margin-right: -5px;
  }
  .legend-row .root-sign {
    font-family: "Times New Roman", serif;
    font-size: 1.2em;
    line-height: 1.05;
  }
  .legend-row .radicand {
    border-top: 1.5px solid currentColor;
    padding: 1px 2px 0 1px;
    margin-left: -1px;
    line-height: 1.15;
  }
  .legend-board {
    margin-left: auto;
    font-size: 12px;
    color: var(--on-surface-variant);
  }

  .slider-row {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 6px 0;
  }
  .slider-label {
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 14px;
    min-width: 110px;
  }
  .slider-row input { flex: 1; accent-color: var(--primary); }

  .note {
    margin-top: 18px;
    font-size: 13px;
    color: var(--on-surface-variant);
  }

  .message {
    text-align: center;
    padding: 72px 16px;
  }
  .message h1 { font-size: 20px; margin: 0 0 8px; }
  .message p { color: var(--on-surface-variant); margin: 0; }

/* Parola sıfırlama sayfası */
.reset-form {
  max-width: 380px;
  margin: 56px auto;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--outline-variant);
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.reset-form h1 { font-size: 20px; margin: 0 0 8px; }
.reset-form label { font-size: 13px; color: var(--on-surface-variant); }
.reset-form input {
  height: 44px;
  padding: 0 12px;
  font-size: 16px;
  color: var(--on-surface);
  background: var(--bg);
  border: 1px solid var(--outline-variant);
  border-radius: 6px;
}
.reset-form .hint { font-size: 12px; color: var(--on-surface-variant); margin: 0 0 8px; }
.reset-form button {
  height: 46px;
  font-size: 16px;
  color: #fff;
  background: var(--primary);
  border: 0;
  border-radius: 999px;
  cursor: pointer;
}
.reset-form button:disabled { opacity: 0.5; cursor: default; }
.feedback { font-size: 14px; margin: 8px 0 0; min-height: 20px; }
.feedback.error { color: #ba1a1a; }
.feedback.ok { color: var(--on-surface-variant); }