:root {
  color-scheme: dark;
  --bg: #061014;
  --panel: rgba(8, 23, 30, 0.86);
  --panel-strong: rgba(10, 30, 38, 0.95);
  --line: #38dff0;
  --sample: #ffd166;
  --quant: #75f09a;
  --code: #c7a1ff;
  --alert: #ff5c78;
  --text: #f1fbff;
  --muted: #a8c0c7;
  --border: rgba(165, 238, 255, 0.24);
  --shadow: rgba(56, 223, 240, 0.24);
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: "Yu Gothic", "Hiragino Kaku Gothic ProN", Meiryo, system-ui, sans-serif;
}

button,
input,
output {
  font: inherit;
}

button {
  border: 0;
}

#stage {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  display: block;
}

.start-overlay {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: grid;
  place-items: center;
  padding: 28px;
  background:
    linear-gradient(140deg, rgba(3, 8, 12, 0.96), rgba(8, 26, 31, 0.9)),
    repeating-linear-gradient(90deg, rgba(255, 255, 255, 0.03) 0 1px, transparent 1px 42px);
  transition: opacity 420ms ease, visibility 420ms ease;
}

.start-overlay.is-hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.start-panel {
  width: min(780px, 92vw);
  padding: 34px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: linear-gradient(160deg, rgba(8, 24, 31, 0.96), rgba(18, 18, 34, 0.92));
  box-shadow: 0 0 42px var(--shadow), inset 0 0 28px rgba(255, 255, 255, 0.035);
  text-align: center;
}

.start-kicker {
  margin-bottom: 12px;
  color: var(--sample);
  font-size: 18px;
  font-weight: 900;
}

.start-panel h1 {
  margin: 0;
  font-size: clamp(36px, 6vw, 58px);
  line-height: 1.14;
}

.start-panel p {
  margin: 18px auto 0;
  max-width: 58ch;
  color: var(--muted);
  font-size: 20px;
  line-height: 1.7;
}

.start-note {
  font-size: 15px !important;
}

.primary-button,
.secondary-button {
  min-height: 42px;
  border-radius: 8px;
  font-weight: 900;
  cursor: pointer;
  transition: transform 150ms ease, filter 150ms ease, border-color 150ms ease, background 150ms ease;
}

.start-button {
  margin-top: 28px;
  width: min(460px, 100%);
  padding: 18px 24px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 8px;
  color: #041015;
  background: linear-gradient(90deg, var(--line), var(--quant) 52%, var(--sample));
  box-shadow: 0 0 24px rgba(56, 223, 240, 0.42);
  cursor: pointer;
  transition: transform 160ms ease, filter 160ms ease;
}

.start-button:hover,
.start-button:focus-visible,
.primary-button:hover,
.primary-button:focus-visible,
.secondary-button:hover,
.secondary-button:focus-visible {
  transform: translateY(-1px);
  filter: brightness(1.08);
  outline: none;
}

.start-button span,
.start-button strong {
  display: block;
}

.start-button span {
  font-size: clamp(18px, 2.6vw, 24px);
  font-weight: 800;
}

.start-button strong {
  margin-top: 4px;
  font-size: clamp(13px, 1.7vw, 16px);
}

.primary-button {
  padding: 12px 20px;
  color: #041014;
  background: linear-gradient(90deg, var(--line), var(--quant) 55%, var(--sample));
  box-shadow: 0 0 22px rgba(56, 223, 240, 0.34);
}

.secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 150px;
  padding: 11px 16px;
  color: var(--text);
  border: 1px solid var(--border);
  background: rgba(9, 27, 34, 0.86);
}

.hud {
  position: fixed;
  z-index: 7;
  top: 18px;
  left: 24px;
  right: 24px;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  pointer-events: none;
}

.hud-main {
  min-width: 0;
}

.hud-label {
  color: var(--muted);
  font-size: 15px;
  font-weight: 800;
}

.hud-title {
  margin-top: 3px;
  font-size: clamp(28px, 4.2vw, 40px);
  line-height: 1.15;
  font-weight: 1000;
  text-shadow: 0 0 18px rgba(56, 223, 240, 0.36);
}

.hud-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  background: var(--panel);
  font-size: 14px;
  font-weight: 900;
  backdrop-filter: blur(12px);
}

.badge-source {
  color: var(--sample);
}

.info-panel {
  position: fixed;
  z-index: 8;
  right: 24px;
  top: 106px;
  width: min(330px, calc(100vw - 48px));
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 0 24px rgba(56, 223, 240, 0.14);
  backdrop-filter: blur(14px);
}

.info-panel-title {
  color: var(--sample);
  font-size: 15px;
  font-weight: 1000;
  margin-bottom: 8px;
}

.info-panel dl {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 7px 14px;
  margin: 0;
}

.info-panel dt,
.info-panel dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.25;
}

.info-panel dt {
  color: var(--muted);
  font-weight: 800;
}

.info-panel dd {
  color: var(--text);
  font-weight: 1000;
  text-align: right;
}

.camera-panel,
.adjust-panel {
  position: fixed;
  z-index: 10;
  left: 24px;
  right: 24px;
  bottom: 94px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: rgba(6, 18, 23, 0.9);
  box-shadow: 0 0 22px rgba(56, 223, 240, 0.12);
  backdrop-filter: blur(14px);
}

.camera-panel {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 12px;
}

.adjust-panel {
  display: grid;
  grid-template-columns: repeat(4, minmax(160px, 1fr)) minmax(120px, 0.5fr);
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
}

.control-row {
  display: grid;
  grid-template-columns: 7.4em minmax(80px, 1fr) 4.4em;
  align-items: center;
  gap: 9px;
  margin: 0;
  color: var(--text);
  font-size: 14px;
  font-weight: 900;
}

.control-row input[type="range"] {
  min-width: 0;
  accent-color: var(--quant);
}

.control-row output {
  color: var(--sample);
  min-width: 4.4em;
  text-align: left;
  justify-self: start;
  font-weight: 1000;
}

.compress-switch {
  width: 100%;
  min-height: 46px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 8px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  background: rgba(9, 27, 34, 0.86);
  box-shadow: 0 0 18px rgba(56, 223, 240, 0.16);
  font-weight: 1000;
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.compress-switch:hover,
.compress-switch:focus-visible {
  transform: translateY(-1px);
  outline: none;
  border-color: rgba(117, 240, 154, 0.58);
}

.switch-track {
  position: relative;
  width: 52px;
  height: 26px;
  flex: 0 0 auto;
  border-radius: 999px;
  border: 1px solid rgba(165, 238, 255, 0.34);
  background: rgba(255, 255, 255, 0.12);
}

.switch-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--muted);
  box-shadow: 0 0 10px rgba(168, 192, 199, 0.4);
  transition: transform 160ms ease, background 160ms ease, box-shadow 160ms ease;
}

.compress-switch.is-on {
  border-color: rgba(117, 240, 154, 0.76);
  background: rgba(12, 44, 38, 0.9);
}

.compress-switch.is-on .switch-track {
  border-color: rgba(117, 240, 154, 0.72);
  background: rgba(117, 240, 154, 0.24);
}

.compress-switch.is-on .switch-thumb {
  transform: translateX(26px);
  background: var(--quant);
  box-shadow: 0 0 14px var(--quant);
}

.notice {
  position: fixed;
  z-index: 16;
  left: 24px;
  bottom: 188px;
  max-width: min(650px, calc(100vw - 48px));
  padding: 12px 14px;
  border: 1px solid rgba(255, 209, 102, 0.44);
  border-radius: 8px;
  color: #fff3c0;
  background: rgba(40, 29, 8, 0.92);
  box-shadow: 0 0 18px rgba(255, 209, 102, 0.18);
  font-weight: 900;
}

.step-splash {
  position: fixed;
  z-index: 15;
  inset: 0;
  display: grid;
  place-items: center;
  color: var(--text);
  font-size: clamp(48px, 9vw, 96px);
  font-weight: 1000;
  text-align: center;
  text-shadow: 0 0 26px rgba(56, 223, 240, 0.68), 0 0 54px rgba(199, 161, 255, 0.34);
  pointer-events: none;
}

.step-splash.is-visible {
  animation: splash-pop 860ms ease forwards;
}

@keyframes splash-pop {
  0% {
    opacity: 0;
    transform: scale(0.72);
  }
  18% {
    opacity: 1;
    transform: scale(1.05);
  }
  74% {
    opacity: 0.92;
    transform: scale(1);
  }
  100% {
    opacity: 0;
    transform: scale(0.96);
  }
}

.flash {
  position: fixed;
  z-index: 14;
  inset: 0;
  background: white;
  opacity: 0;
  pointer-events: none;
}

.flash.is-active {
  animation: camera-flash 420ms ease-out;
}

@keyframes camera-flash {
  0% {
    opacity: 0;
  }
  12% {
    opacity: 0.94;
  }
  100% {
    opacity: 0;
  }
}

.frame-flash {
  position: fixed;
  z-index: 13;
  inset: 8px;
  border: 2px solid rgba(56, 223, 240, 0);
  border-radius: 8px;
  pointer-events: none;
}

.frame-flash.is-active {
  animation: frame-flash 430ms ease-out;
}

@keyframes frame-flash {
  0% {
    border-color: rgba(56, 223, 240, 0.95);
    box-shadow: inset 0 0 20px rgba(56, 223, 240, 0.55), 0 0 24px rgba(56, 223, 240, 0.4);
  }
  100% {
    border-color: rgba(56, 223, 240, 0);
    box-shadow: none;
  }
}

.legend {
  position: fixed;
  z-index: 6;
  left: 0;
  right: 0;
  bottom: 0;
  min-height: 78px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  padding: 10px 18px 14px;
  background: linear-gradient(180deg, rgba(3, 9, 12, 0.68), rgba(3, 9, 12, 0.96));
  border-top: 1px solid var(--border);
  backdrop-filter: blur(14px);
}

.legend-item {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-width: 0;
  padding: 8px 10px;
  color: var(--muted);
  font-size: clamp(13px, 1.7vw, 20px);
  font-weight: 900;
  border-radius: 8px;
  transition: color 220ms ease, background 220ms ease, transform 220ms ease;
}

.legend-item.is-active {
  color: var(--text);
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-2px);
}

.legend-item.is-complete::after {
  content: "✓";
  display: inline-grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  color: #041015;
  background: var(--quant);
  font-size: 14px;
  font-weight: 1000;
}

.legend-icon {
  position: relative;
  width: 44px;
  height: 28px;
  flex: 0 0 auto;
}

.icon-camera::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  width: 28px;
  height: 18px;
  border-radius: 4px;
  border: 3px solid var(--line);
  box-shadow: 0 0 12px var(--line);
}

.icon-camera::after {
  content: "";
  position: absolute;
  right: 1px;
  top: 9px;
  border-left: 12px solid var(--line);
  border-top: 6px solid transparent;
  border-bottom: 6px solid transparent;
  filter: drop-shadow(0 0 8px var(--line));
}

.icon-frames::before,
.icon-frames::after {
  content: "";
  position: absolute;
  top: 4px;
  width: 20px;
  height: 18px;
  border-radius: 3px;
  border: 2px solid var(--sample);
  box-shadow: 0 0 10px var(--sample);
}

.icon-frames::before {
  left: 3px;
}

.icon-frames::after {
  right: 3px;
  transform: translateY(4px);
}

.icon-encoding::before {
  content: "01";
  position: absolute;
  inset: 0;
  color: var(--code);
  font-family: Consolas, "Courier New", monospace;
  font-size: 24px;
  line-height: 28px;
  font-weight: 1000;
  text-shadow: 0 0 12px var(--code);
}

.icon-compression::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 4px;
  width: 36px;
  height: 20px;
  border-radius: 4px;
  background:
    linear-gradient(90deg, transparent 0 36%, var(--quant) 36% 44%, transparent 44% 56%, var(--alert) 56% 64%, transparent 64% 100%),
    linear-gradient(135deg, rgba(56, 223, 240, 0.35), rgba(199, 161, 255, 0.35));
  border: 2px solid var(--quant);
  box-shadow: 0 0 12px var(--quant);
}

.legend-item.is-active .legend-icon {
  animation: legend-pulse 900ms ease-in-out infinite alternate;
}

@keyframes legend-pulse {
  from {
    filter: drop-shadow(0 0 4px currentColor);
    transform: scale(1);
  }
  to {
    filter: drop-shadow(0 0 16px currentColor);
    transform: scale(1.12);
  }
}

@media (max-width: 1100px) {
  .adjust-panel {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .compress-switch {
    grid-column: span 2;
  }
}

@media (max-width: 760px) {
  .hud {
    top: 12px;
    left: 14px;
    right: 14px;
    flex-direction: column;
  }

  .hud-badges {
    justify-content: flex-start;
  }

  .camera-panel,
  .adjust-panel {
    left: 14px;
    right: 14px;
    bottom: 92px;
  }

  .camera-panel {
    flex-wrap: wrap;
  }

  .adjust-panel {
    grid-template-columns: 1fr;
  }

  .compress-switch {
    grid-column: auto;
  }

  .control-row {
    grid-template-columns: 7.2em minmax(80px, 1fr) 4.2em;
    font-size: 13px;
  }

  .info-panel {
    top: auto;
    right: 14px;
    bottom: 166px;
  }

  .notice {
    left: 14px;
    bottom: auto;
    top: 118px;
  }

  .legend {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    min-height: 86px;
    padding: 8px 8px 10px;
  }
}

/*
  授業用プレゼン教材のため、OS側の reduced motion 設定では演出を止めない。
*/