:root {
  --bg: #0f1216;
  --fg: #e7ebf0;
  --muted: #9aa4b2;
  --card: #171b21;
  --accent: #4da3ff;
  --ok: #2ecc71;
  --warn: #ffb020;
  --danger: #ff5d5d;
  --border: #2a3038;
}

:root.light {
  --bg: #ffffff;
  --fg: #1a1f26;
  --muted: #6b7280;
  --card: #f3f4f6;
  --accent: #2563eb;
  --ok: #10b981;
  --warn: #f59e0b;
  --danger: #ef4444;
  --border: #d1d5db;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--fg); font-family: system-ui, -apple-system, Segoe UI, Roboto, Noto Sans JP, sans-serif; }

.site-header { padding: 16px; border-bottom: 1px solid var(--border); }
.topbar { display: flex; justify-content: center; align-items: center; }
.brand { text-align: center; }
.brand h1 { margin: 0; font-size: 28px; }
.subtitle { margin: 6px 0 0; color: var(--muted); font-size: 14px; }

.sr { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

.container { max-width: 1100px; margin: 0 auto; padding: 16px; }

.nav-wrapper { display: flex; justify-content: center; align-items: center; margin-bottom: 12px; position: relative; padding: 0 180px; }
@media (max-width: 750px) { 
  .nav-wrapper { padding: 0; flex-direction: column; gap: 12px; } 
  .controls-switch { position: static; }
}
.tabs { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; }
.controls-switch { 
  position: absolute; 
  right: 0; 
  display: flex; 
  gap: 8px; 
  align-items: center;
}
.lang-toggle-btn { 
  background: var(--card); 
  color: var(--fg); 
  border: 1px solid var(--border); 
  border-radius: 10px; 
  padding: 8px 16px; 
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s ease;
}
.lang-toggle-btn:hover { 
  border-color: var(--accent); 
  background: color-mix(in srgb, var(--accent) 10%, var(--card));
}
.lang-toggle-btn:active { transform: scale(0.98); }
.lang-toggle-btn:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 30%, transparent); }

.theme-toggle-btn { 
  background: var(--card); 
  color: var(--fg); 
  border: 1px solid var(--border); 
  border-radius: 10px; 
  padding: 8px 12px; 
  cursor: pointer;
  font-size: 16px;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
}
.theme-toggle-btn:hover { 
  border-color: var(--accent); 
  background: color-mix(in srgb, var(--accent) 10%, var(--card));
}
.theme-toggle-btn:active { transform: scale(0.98); }
.theme-toggle-btn:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 30%, transparent); }
.tab-button { background: var(--card); border: 1px solid var(--border); color: var(--fg); padding: 10px 16px; border-radius: 999px; cursor: pointer; }
.tab-button.active { border-color: var(--accent); box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 30%, transparent); }
.tab-content { display: none; }
.tab-content.active { display: block; }

.card { background: var(--card); border: 1px solid var(--border); border-radius: 16px; padding: 16px; box-shadow: 0 6px 24px rgba(0,0,0,.25); }
.grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
@media (max-width: 900px){ .grid{ grid-template-columns: 1fr; } }

.controls { display: flex; gap: 8px; margin: 8px 0; flex-wrap: wrap; align-items: center; justify-content: center; }
button { background: var(--card); color: var(--fg); border: 1px solid var(--border); border-radius: 10px; padding: 8px 12px; cursor: pointer; }
button:hover { border-color: var(--accent); }
button.secondary { background: transparent; }
label input { margin-left: 6px; width: 80px; background: var(--card); color: var(--fg); border: 1px solid var(--border); border-radius: 6px; padding: 4px 8px; }

.hint, .note { color: var(--muted); }
.hint { text-align: center; }
.note { 
  background: color-mix(in srgb, var(--warn) 10%, transparent); 
  border: 1px solid color-mix(in srgb, var(--warn) 30%, transparent); 
  border-radius: 8px; 
  padding: 12px; 
  margin-top: 12px;
}

.what-is-grid {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 20px;
  margin-top: 16px;
  align-items: start;
}

@media (max-width: 768px) {
  .what-is-grid {
    grid-template-columns: 1fr;
  }
}

.what-is-text {
  padding-right: 10px;
}

.what-is-text p {
  margin: 12px 0;
  line-height: 1.6;
}

.what-is-image {
  display: flex;
  justify-content: center;
  align-items: start;
}

.what-is-img {
  width: 100%;
  max-width: 300px;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  object-fit: cover;
}

.structure-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 16px;
}

@media (max-width: 768px) {
  .structure-grid {
    grid-template-columns: 1fr;
  }
}

.structure-images {
  display: grid;
  gap: 10px;
}

.structure-img {
  width: 100%;
  max-width: 550px;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  object-fit: cover;
}

.structure-img:nth-child(1) {
  max-width: 650px;
}

.structure-img:nth-child(2) {
  max-width: 650px;
}

.structure-image-bottom {
  margin-top: 20px;
  text-align: center;
}

.structure-img-bottom {
  width: 100%;
  max-width: 650px;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  object-fit: cover;
}

.structure-text h3 {
  margin-top: 0;
  color: var(--accent);
}

.structure-text ul {
  list-style-type: none;
  padding-left: 0;
}

.structure-text li {
  margin: 8px 0;
  padding: 6px 0;
  border-bottom: 1px solid color-mix(in srgb, var(--border) 50%, transparent);
}

.mechanism-grid {
  margin-top: 16px;
}

.mechanism-text {
  text-align: left;
}

.mechanism-states {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin: 20px 0;
}

.mechanism-state {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 20px;
  background: color-mix(in srgb, var(--accent) 3%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 15%, transparent);
  border-radius: 10px;
}

.mechanism-img {
  width: 450px;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 6px;
  flex-shrink: 0;
}

@media (max-width: 768px) {
  .mechanism-state {
    flex-direction: column;
    text-align: center;
  }
  
  .mechanism-img {
    width: 100%;
    max-width: 450px;
  }
}

.mechanism-state p {
  margin: 0;
  font-size: 15px;
  line-height: 1.5;
  text-align: left;
}

.demo-patterns {
  margin: 20px 0;
  padding: 16px;
  background: color-mix(in srgb, var(--accent) 5%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 20%, transparent);
  border-radius: 10px;
}

.demo-patterns h3 {
  margin-top: 0;
  color: var(--accent);
}

.demo-combo-display {
  margin: 12px 0 16px 0;
  padding: 10px 16px;
  background: color-mix(in srgb, var(--ok) 8%, transparent);
  border: 1px solid color-mix(in srgb, var(--ok) 25%, transparent);
  border-radius: 8px;
  text-align: center;
}

.demo-combo-text {
  font-weight: 700;
  font-family: monospace;
  font-size: 18px;
  color: var(--ok);
  margin-left: 8px;
}

.demo-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.demo-btn {
  background: var(--accent);
  color: white;
  border: none;
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.demo-btn:hover {
  background: color-mix(in srgb, var(--accent) 80%, black);
  transform: translateY(-1px);
}

@keyframes successPulse {
  0% {
    transform: translate(-50%, -50%) scale(0.8);
    opacity: 0;
  }
  50% {
    transform: translate(-50%, -50%) scale(1.1);
    opacity: 1;
  }
  100% {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
}

.success-notification {
  animation: successPulse 2s ease-out;
}

.dial-wrap { position: relative; display: grid; place-items: center; margin: 8px 0 12px; }
.dial { position: relative; width: 220px; height: 220px; border-radius: 50%; background: radial-gradient(ellipse at center, color-mix(in srgb, var(--border) 80%, transparent) 0%, color-mix(in srgb, var(--card) 90%, transparent) 70%, var(--card) 100%); border: 2px solid var(--border); user-select: none; }
.dial-face::before {
  content: ""; position: absolute; inset: 10px; border-radius: 50%;
  background:
    conic-gradient(from 0deg, transparent 0 3.6deg, var(--muted) 3.6deg 7.2deg) center/100% 100% no-repeat;
  mask: radial-gradient(circle at center, transparent 42%, black 42% 100%);
}
.dial-face {
  position: relative;
  width: 100%;
  height: 100%;
}

.dial-zero {
  position: absolute; top: 15px; left: 50%; transform: translateX(-50%);
  font-size: 16px; font-weight: 700; color: var(--fg);
  text-align: center; line-height: 1;
}

.dial-indicator {
  position: absolute; top: -18px; left: 50%; transform: translateX(-50%);
  font-size: 18px; color: var(--danger);
  filter: drop-shadow(0 2px 4px rgba(0,0,0,.5));
  line-height: 1;
  z-index: 10;
}
.dial-value {
  position: absolute; bottom: 20px; left: 50%; transform: translateX(-50%);
  padding: 6px 10px; background: var(--card); border: 1px solid var(--border); border-radius: 8px;
  font-weight: 700; letter-spacing: 0.08em; color: var(--fg);
}

.inner-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.inner-header h2 {
  margin: 0;
}

.legend {
  display: flex;
  gap: 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 12px;
}

@media (max-width: 768px) {
  .inner-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  
  .legend {
    align-self: stretch;
    justify-content: center;
  }
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.legend-gate {
  width: 20px;
  height: 6px;
  background: var(--warn);
  border-radius: 3px;
}

.legend-tsuku {
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 50%;
  border: 1px solid color-mix(in srgb, var(--accent) 80%, white);
}

.combination-display {
  margin-bottom: 16px;
  padding: 8px 12px;
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  border-radius: 8px;
  text-align: center;
}

.combination-text {
  font-weight: 700;
  font-family: monospace;
  font-size: 16px;
  color: var(--accent);
}

.combination-note {
  font-size: 14px;
  color: var(--muted);
  margin-left: 8px;
  font-style: italic;
}

.stack { display: grid; gap: 10px; padding: 0 20px; }
.wheel {
  position: relative; height: 60px; background: var(--card); border: 1px solid var(--border); border-radius: 10px; overflow: visible;
}
.wheel-title { position: absolute; left: 10px; top: 8px; color: var(--muted); font-size: 12px; }
.wheel-value { 
  position: absolute; 
  right: 10px; 
  top: 8px; 
  color: var(--fg); 
  font-size: 14px; 
  font-weight: 700; 
  font-family: monospace;
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  border-radius: 4px;
  padding: 2px 6px;
  min-width: 24px;
  text-align: center;
}

.gate {
  position: absolute; top: 50%; height: 10px; width: 40px; background: var(--warn);
  transform: translateY(-50%);
  border-radius: 6px;
  transition: left .08s linear;
  z-index: 1;
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.tsuku {
  position: absolute; top: 50%; height: 14px; width: 14px; background: var(--accent);
  transform: translateY(-50%);
  border-radius: 50%;
  transition: left .08s linear;
  z-index: 2;
  box-shadow: 0 2px 4px rgba(0,0,0,0.3);
  border: 2px solid color-mix(in srgb, var(--accent) 80%, white);
}
.fence { position: relative; margin-top: 6px; height: 54px; background: var(--card); border: 1px solid var(--border); border-radius: 12px; }
.fence::before {
  content: "";
  position: absolute;
  top: -280px; /* Driving Discのバーの上まで延長 */
  left: 50%;
  transform: translateX(-50%);
  width: 2px;
  height: 286px; /* フェンス上部からDriving Discの上まで貫く高さ */
  background: linear-gradient(to bottom, var(--accent) 0%, var(--accent) 20%, transparent 20%, var(--accent) 40%, transparent 40%, var(--accent) 60%, transparent 60%, var(--accent) 80%, transparent 80%, var(--accent) 100%);
  background-size: 2px 6px;
  z-index: 5; /* ディスク要素の上に表示 */
}
.fence-bar {
  position: absolute; left: 50%; transform: translateX(-50%);
  top: 8px; width: 8px; height: 36px; background: var(--muted); border-radius: 4px; transition: top .12s ease;
}
.fence-status { position: absolute; bottom: -30px; width: 100%; text-align: center; color: var(--muted); font-size: 12px; }

.status { margin-top: 35px; display: flex; gap: 18px; color: var(--muted); }

.log, .progress {
  margin-top: 10px; background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 10px; min-height: 60px; color: var(--fg);
}

.open-banner {
  margin-top: 12px; padding: 14px; border-radius: 12px;
  background: color-mix(in srgb, var(--ok) 12%, transparent); border: 1px solid var(--ok); color: var(--ok);
  font-weight: 700; text-align: center; font-size: 18px;
}

footer { margin: 24px 0; }
.footer {
  text-align: center; color: var(--muted);
  padding: 16px; border-top: 1px dashed var(--border);
}
.footer a { color: var(--accent); text-decoration: none; }