:root {
  --ck-bg: #f5f7fa;
  --ck-card: #ffffff;
  --ck-ink: #1b2430;
  --ck-muted: #51606f;
  --ck-line: #cdd6e0;
  --ck-accent: #0a5ca8;
  --ck-accent-soft: #e4effa;
  --ck-warn: #8a4b00;
  --ck-warn-soft: #fff4e2;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 0 14px 36px;
  background: var(--ck-bg);
  color: var(--ck-ink);
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

h1 { font-size: 1.4rem; margin: 6px 0 10px; }
h2 { font-size: 1.08rem; margin: 0 0 8px; }

.skip-link {
  position: absolute;
  left: -9999px;
}
.skip-link:focus {
  position: static;
  display: inline-block;
  margin: 8px 0;
  padding: 10px 14px;
  background: var(--ck-accent);
  color: #fff;
  border-radius: 8px;
}

.ck-header { padding-top: 18px; max-width: 760px; margin: 0 auto; }
.ck-kicker { margin: 0; color: var(--ck-muted); font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.04em; }
.ck-lead { margin: 0; color: var(--ck-muted); }

.ck-notice,
.ck-modes,
.ck-diagram-wrap,
.ck-controls,
.ck-explain,
.ck-links {
  max-width: 760px;
  margin: 14px auto;
  padding: 14px;
  background: var(--ck-card);
  border: 1px solid var(--ck-line);
  border-radius: 12px;
}

.ck-notice {
  background: var(--ck-warn-soft);
  border-color: #e9c89a;
  color: var(--ck-warn);
}
.ck-notice ul { margin: 0; padding-left: 20px; }
.ck-notice li + li { margin-top: 6px; }

.ck-hint { margin: 6px 0 0; color: var(--ck-muted); font-size: 0.88rem; }

.ck-segmented {
  display: flex;
  gap: 8px;
  margin-top: 10px;
}
.ck-tab {
  flex: 1 1 0;
  min-height: 48px;
  min-width: 44px;
  padding: 10px 12px;
  font: inherit;
  font-weight: 600;
  color: var(--ck-accent);
  background: var(--ck-accent-soft);
  border: 2px solid var(--ck-accent);
  border-radius: 10px;
  cursor: pointer;
}
.ck-tab[aria-selected="true"] {
  background: var(--ck-accent);
  color: #fff;
}

.ck-layout { max-width: 760px; margin: 0 auto; }
.ck-layout:focus-visible,
.ck-tab:focus-visible,
.ck-control-btn:focus-visible,
a:focus-visible {
  outline: 3px solid #b8450a;
  outline-offset: 2px;
}

.ck-diagram {
  display: block;
  width: 100%;
  height: auto;
  max-width: 420px;
  margin: 10px auto 0;
  background: #fbfcfe;
  border: 1px solid var(--ck-line);
  border-radius: 10px;
}
.ck-part rect,
.ck-part circle,
.ck-part path { fill: #dfe6ee; stroke: #8b98a6; stroke-width: 2; }
.ck-part .ck-glyph { fill: #8b98a6; stroke: none; }
.ck-part text { fill: var(--ck-muted); font-size: 10px; text-anchor: middle; stroke: none; }
.ck-part .ck-inner { fill: #fff; }
.ck-part[hidden] { display: none; }
.ck-part.is-active rect,
.ck-part.is-active circle,
.ck-part.is-active path { fill: #ffdca8; stroke: #b8450a; stroke-width: 3; }
.ck-part.is-active .ck-glyph { fill: #b8450a; }
.ck-part.is-active text { fill: #8a3a06; font-weight: 700; }
.ck-part.is-active .ck-inner { fill: #fff; }

.ck-legend { margin: 8px 0 0; color: var(--ck-muted); font-size: 0.85rem; text-align: center; }

.ck-control-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.ck-control-btn {
  display: block;
  width: 100%;
  min-height: 48px;
  padding: 12px 14px;
  font: inherit;
  text-align: left;
  color: var(--ck-ink);
  background: #f8fafc;
  border: 1px solid var(--ck-line);
  border-radius: 10px;
  cursor: pointer;
}
.ck-control-btn[aria-pressed="true"] {
  background: #fff3e0;
  border-color: #b8450a;
  box-shadow: inset 0 0 0 1px #b8450a;
  font-weight: 600;
}
.ck-control-tag { display: block; color: var(--ck-muted); font-size: 0.82rem; font-weight: 400; }

.ck-explain-body h3 { margin: 0 0 6px; font-size: 1rem; }
.ck-explain-body p { margin: 0 0 8px; }
.ck-explain-body ul { margin: 0 0 8px; padding-left: 20px; }
.ck-placeholder { color: var(--ck-muted); }
.ck-explain-note { color: var(--ck-warn); font-size: 0.88rem; }

.ck-links ul { margin: 0; padding-left: 20px; }
.ck-links a { color: var(--ck-accent); }

.ck-footer {
  max-width: 760px;
  margin: 18px auto 0;
  color: var(--ck-muted);
  font-size: 0.85rem;
  text-align: center;
}

@media (min-width: 720px) {
  .ck-control-list { grid-template-columns: 1fr 1fr; }
}

@media (prefers-contrast: more) {
  .ck-part rect, .ck-part circle, .ck-part path { stroke: #000; }
}