@charset "UTF-8";

:root {
  font-family: system-ui, -apple-system, sans-serif;
  color: #182b49;
  background-color: #ccffff;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
}

button,
select,
input {
  font: inherit;
}

button,
select,
summary,
input[type='checkbox'] {
  cursor: pointer;
}

button,
select {
  min-height: 44px;
  padding: 8px 14px;
  color: #182b49;
  background: #ffffff;
  border: 1px solid #9eacc9;
  border-radius: 8px;
}

button {
  touch-action: manipulation;
}

button:disabled {
  cursor: default;
  opacity: 0.4;
}

:focus-visible {
  outline: 3px solid #285bc7;
  outline-offset: 3px;
}

a {
  color: #254da1;
  text-underline-offset: 3px;
}

p {
  line-height: 1.8;
}

#contents {
  max-width: 1180px;
  min-height: 100vh;
  padding: 0 24px;
  margin: 0 auto;
  background-color: #ffffff;
}

header {
  padding: 23px 0 10px;
  text-align: center;
}

h1 {
  margin: 0;
  font-size: clamp(1.2rem, 3.8vw, 1.8rem);
  color: #000055;
}

#version-info {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: normal;
  color: #576684;
  white-space: nowrap;
}

.intro {
  margin: 9px 0;
  color: #4d5d73;
}

.line-controls,
.playback-controls,
.settings,
.speed-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  justify-content: center;
}

.line-controls {
  padding-bottom: 16px;
  border-bottom: 1px solid #dce3ef;
}

.line-controls > label {
  font-weight: 600;
}

#line-select {
  min-width: 154px;
}

#line-count {
  min-width: 4em;
  font-variant-numeric: tabular-nums;
  color: #576684;
}

.visuals {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.visual-panel {
  min-width: 0;
  overflow: hidden;
  border: 1px solid #c8d2e6;
  border-radius: 12px;
}

.visual-panel h2 {
  padding: 9px 16px;
  margin: 0;
  font-size: 1rem;
  color: #000055;
  background-color: #dce3ff;
}

svg {
  display: block;
  width: 100%;
  height: auto;
  user-select: none;
}

.board-scroll {
  overflow-x: auto;
}

#svg-board {
  min-width: 470px;
}

.board-hint {
  margin: 8px 10px 12px;
  font-size: 0.8rem;
  text-align: center;
}

.scroll-note {
  display: none;
}

.guide-circle {
  fill: none;
  stroke: #e0e6ee;
  stroke-dasharray: 5 7;
}

.guide-axis {
  fill: none;
  stroke: #e0e6ee;
}

.angle-summary {
  display: flex;
  flex-wrap: wrap;
  gap: 3px 16px;
  align-items: baseline;
  justify-content: center;
  padding: 0 10px 12px;
  font-variant-numeric: tabular-nums;
}

#angle-total {
  font-size: 1.25rem;
  color: #000055;
}

#pi-total {
  font-size: 0.85rem;
  color: #576684;
}

.playback-panel {
  padding: 20px;
  margin-top: 18px;
  background-color: #f3f6ff;
  border: 1px solid #c8d2e6;
  border-radius: 12px;
}

.progress-heading {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  align-items: baseline;
  justify-content: space-between;
  margin-top: 16px;
}

#step-count {
  margin-left: 8px;
  font-variant-numeric: tabular-nums;
}

#phase-info {
  min-height: 1.5em;
  font-size: 0.9rem;
  color: #435679;
}

#progress {
  width: 100%;
  height: 32px;
  margin: 8px 0 13px;
  accent-color: #3663ba;
}

.playback-controls button {
  min-width: 110px;
}

.playback-controls .play-button {
  color: #164e2b;
  background-color: #bcf0cb;
  border-color: #68ad80;
}

.playback-controls .play-button:hover {
  background-color: #a1e5b6;
}

.playback-controls .reset-button {
  background-color: #efdbff;
  border-color: #b693d2;
}

.settings {
  gap: 12px 22px;
  margin-top: 16px;
}

.settings label {
  display: inline-flex;
  gap: 7px;
  align-items: center;
  min-height: 44px;
}

input[type='checkbox'] {
  width: 19px;
  height: 19px;
  margin: 0;
  accent-color: #3663ba;
}

.speed-controls {
  gap: 8px;
}

.speed-controls button {
  min-width: 44px;
  color: #714000;
  background-color: #fff2be;
  border-color: #c6a04c;
}

#speed-info {
  min-width: 6.5em;
  font-variant-numeric: tabular-nums;
  text-align: center;
}

.control-note {
  margin: 12px 0 0;
  font-size: 0.8rem;
  color: #576684;
}

.fraction-details,
.shortcuts {
  padding: 14px 18px;
  margin-top: 18px;
  border: 1px solid #c8d2e6;
  border-radius: 9px;
}

summary {
  padding: 3px 0;
  font-weight: 600;
}

.table-scroll {
  overflow-x: auto;
}

table {
  width: 100%;
  margin-top: 14px;
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  border-collapse: collapse;
}

th,
td {
  padding: 9px 12px;
  text-align: right;
  white-space: nowrap;
  border-bottom: 1px solid #dce3ef;
}

th {
  background-color: #eef2ff;
}

tbody tr[aria-current='step'] {
  background-color: #fff0a2;
}

.validation-info {
  margin: 12px 0 24px;
  font-size: 0.8rem;
  color: #526278;
}

.explanation {
  padding-top: 18px;
  border-top: 1px solid #c8d2e6;
}

.explanation h2 {
  margin-top: 0;
  font-size: 1.2rem;
  color: #000055;
}

.source-links {
  font-size: 0.85rem;
}

dl {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px 24px;
  align-items: baseline;
}

dd {
  margin: 0;
}

kbd {
  padding: 2px 6px;
  font-family: inherit;
  font-size: 0.85rem;
  background-color: #f3f6ff;
  border: 1px solid #c8d2e6;
  border-radius: 4px;
}

footer {
  padding: 20px 0;
  font-size: 0.85rem;
  text-align: center;
}

.notice {
  padding: 12px;
  color: #732828;
  background-color: #fff0ed;
  border: 1px solid #dbaca6;
}

button:where(:hover):not(:disabled) {
  background-color: #e8eeff;
}

@media (width <= 760px) {
  .scroll-note {
    display: inline;
  }

  #contents {
    padding: 0 12px;
  }

  header {
    padding-top: 18px;
  }

  .intro {
    font-size: 0.9rem;
  }

  .visuals {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .line-controls {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 8px;
  }

  .line-controls > label {
    grid-column: 1 / 3;
    text-align: left;
  }

  #line-select {
    width: 100%;
    min-width: 0;
  }

  #line-count {
    grid-row: 1;
    grid-column: 3;
    text-align: right;
  }

  .playback-panel {
    padding: 15px 12px;
  }

  .playback-controls {
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 8px;
  }

  .playback-controls button {
    grid-column: span 2;
    min-width: 0;
    padding: 8px 4px;
    font-size: 0.8125rem;
    white-space: nowrap;
  }

  .playback-controls .reset-button {
    grid-column: span 3;
  }

  .settings {
    gap: 6px 16px;
  }

  .speed-controls {
    width: 100%;
  }

  .control-note {
    line-height: 1.6;
  }

  dl {
    grid-template-columns: 1fr;
    gap: 7px;
  }

  dd {
    margin-bottom: 8px;
  }
}