:root {
  color-scheme: dark;
  --bg: #07110f;
  --panel: #0d1c19;
  --panel-strong: #102824;
  --line: #2d554b;
  --line-soft: rgba(129, 200, 181, 0.2);
  --text: #e9f7f1;
  --muted: #a9c3ba;
  --signal: #89ffd1;
  --signal-strong: #33e99f;
  --amber: #ffd37a;
  --danger: #ff7c70;
  --ink: #04110d;
  --shadow: 0 18px 54px rgba(0, 0, 0, 0.38);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--bg);
}

body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  color: var(--text);
  background:
    radial-gradient(circle at 15% 0%, rgba(51, 233, 159, 0.12), transparent 30rem),
    linear-gradient(180deg, #07110f 0%, #040908 100%);
  font-family: "Hiragino Sans", "Yu Gothic UI", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.7;
}

button,
input {
  font: inherit;
}

button,
a,
input[type="range"] {
  -webkit-tap-highlight-color: transparent;
}

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 3px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 18px 0 14px;
  border-bottom: 1px solid var(--line-soft);
}

.site-header .brand {
  color: var(--text);
  font-weight: 800;
  text-decoration: none;
  letter-spacing: 0.02em;
}

.site-header p {
  margin: 0;
  color: var(--signal);
  font: 700 0.76rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.app-shell {
  width: min(1020px, calc(100% - 32px));
  margin: 0 auto;
  padding: 34px 0 64px;
}

.mode-intro {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 22px;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--signal);
  font: 800 0.73rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.18em;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: clamp(1.8rem, 5vw, 2.75rem);
  line-height: 1.15;
  letter-spacing: 0.01em;
}

h1 small {
  display: block;
  margin-top: 7px;
  color: var(--muted);
  font: 700 0.38em/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

h2 {
  margin: 0;
  font-size: clamp(1.25rem, 3vw, 1.65rem);
  line-height: 1.3;
}

.lead {
  margin: 12px 0 0;
  color: var(--muted);
  font-weight: 700;
}

.channel-badge {
  flex: 0 0 auto;
  min-width: 134px;
  padding: 13px 18px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: linear-gradient(145deg, rgba(22, 58, 49, 0.9), rgba(8, 25, 21, 0.9));
  box-shadow: inset 0 0 24px rgba(51, 233, 159, 0.06);
  text-align: center;
}

.channel-badge span,
.channel-badge small {
  display: block;
  color: var(--muted);
  font: 700 0.64rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.12em;
}

.channel-badge strong {
  display: block;
  margin: 2px 0;
  color: var(--signal);
  font: 800 2.2rem/1 ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.audio-check,
.status-panel,
.receiver,
.input-panel,
.result-panel,
.how-to,
.related-modes {
  border: 1px solid var(--line-soft);
  border-radius: 18px;
  background: linear-gradient(150deg, rgba(16, 40, 36, 0.97), rgba(8, 22, 19, 0.97));
  box-shadow: var(--shadow);
}

.audio-check {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.85fr);
  gap: 18px 28px;
  padding: 20px 22px;
  margin-bottom: 18px;
}

.audio-check p {
  margin: 6px 0 0;
  color: var(--muted);
}

.audio-controls {
  display: grid;
  grid-template-columns: 1fr auto;
  align-content: center;
  gap: 10px 14px;
}

.audio-controls label {
  display: flex;
  justify-content: space-between;
  grid-column: 1 / -1;
  color: var(--muted);
  font-weight: 700;
}

.audio-controls input[type="range"] {
  width: 100%;
  accent-color: var(--signal-strong);
}

.audio-check-status {
  grid-column: 1 / -1;
  padding-top: 10px;
  border-top: 1px solid var(--line-soft);
  color: var(--muted);
  font-size: 0.9rem;
}

.audio-check.is-ready {
  border-color: rgba(51, 233, 159, 0.55);
}

.audio-check.is-ready .audio-check-status {
  color: var(--signal);
}

.game-shell {
  display: grid;
  gap: 14px;
}

.status-panel {
  padding: 18px 20px;
}

.status-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.status-head > div:first-child {
  min-width: 0;
}

#status-code {
  display: block;
  margin-bottom: 3px;
  color: var(--signal);
  font: 800 0.7rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.16em;
}

#status-message {
  display: block;
  line-height: 1.4;
}

.status-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 10px;
}

.primary-button,
.secondary-button,
.replay-button {
  min-height: 46px;
  border-radius: 11px;
  padding: 10px 18px;
  border: 1px solid transparent;
  cursor: pointer;
  font-weight: 800;
  transition: transform 120ms ease, filter 120ms ease, background-color 120ms ease;
}

.primary-button {
  color: var(--ink);
  background: var(--signal);
  box-shadow: 0 8px 24px rgba(51, 233, 159, 0.18);
}

.secondary-button,
.replay-button {
  color: var(--text);
  border-color: var(--line);
  background: #17362f;
}

.primary-button:hover:not(:disabled),
.secondary-button:hover:not(:disabled),
.replay-button:hover:not(:disabled) {
  filter: brightness(1.12);
  transform: translateY(-1px);
}

button:disabled {
  cursor: not-allowed;
  filter: grayscale(0.65);
  opacity: 0.52;
}

.status-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin: 16px 0 0;
}

.status-metrics div {
  min-width: 0;
  padding: 10px 12px;
  border: 1px solid var(--line-soft);
  border-radius: 11px;
  background: rgba(3, 14, 11, 0.55);
}

.status-metrics dt {
  color: var(--muted);
  font-size: 0.74rem;
  font-weight: 700;
}

.status-metrics dd {
  margin: 2px 0 0;
  color: var(--signal);
  font: 800 1.2rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.receiver {
  position: relative;
  overflow: hidden;
  padding: 20px;
}

.receiver::before {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(180deg, transparent 0 4px, rgba(137, 255, 209, 0.025) 5px);
  content: "";
}

.receiver-head,
.signal-label-row {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.signal-state {
  padding: 7px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  background: rgba(2, 12, 9, 0.72);
  font: 800 0.75rem/1 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.12em;
}

.signal-state[data-state="clear"] {
  color: var(--signal);
  border-color: rgba(51, 233, 159, 0.55);
}

.signal-state[data-state="static"] {
  color: var(--amber);
  border-color: rgba(255, 211, 122, 0.55);
}

.signal-state[data-state="drop"] {
  color: var(--danger);
  border-color: rgba(255, 124, 112, 0.55);
}

.signal-display {
  position: relative;
  display: grid;
  align-items: center;
  min-height: 116px;
  margin: 18px 0;
  overflow: hidden;
  border: 1px solid rgba(137, 255, 209, 0.22);
  border-radius: 14px;
  background:
    linear-gradient(90deg, transparent 49.7%, rgba(137, 255, 209, 0.12) 50%, transparent 50.3%),
    linear-gradient(180deg, transparent 49%, rgba(137, 255, 209, 0.1) 50%, transparent 51%),
    #03100c;
}

.waveform {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(4px, 1.3vw, 12px);
  height: 92px;
  padding: 0 20px;
  opacity: 0.38;
}

.waveform i {
  width: clamp(3px, 0.55vw, 6px);
  height: 12px;
  border-radius: 4px;
  background: var(--signal);
  box-shadow: 0 0 12px rgba(137, 255, 209, 0.5);
  transform-origin: center;
}

.receiver.is-playing .waveform {
  opacity: 1;
}

.receiver.is-playing .waveform i {
  animation: pulse-wave 760ms ease-in-out infinite alternate;
}

.receiver.is-playing .waveform i:nth-child(2n) { animation-delay: -300ms; }
.receiver.is-playing .waveform i:nth-child(3n) { animation-delay: -510ms; }
.receiver.is-playing .waveform i:nth-child(5n) { animation-delay: -160ms; }

@keyframes pulse-wave {
  0% { transform: scaleY(0.8); }
  35% { transform: scaleY(3.8); }
  70% { transform: scaleY(1.7); }
  100% { transform: scaleY(5.2); }
}

.frequency {
  position: absolute;
  right: 12px;
  bottom: 8px;
  color: rgba(169, 195, 186, 0.66);
  font: 700 0.64rem/1 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.1em;
}

.signal-meter-wrap {
  position: relative;
}

.signal-label-row {
  margin-bottom: 6px;
  color: var(--muted);
  font: 800 0.7rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.12em;
}

#signal-meter {
  display: block;
  width: 100%;
  height: 16px;
  overflow: hidden;
  border: 0;
  border-radius: 999px;
  background: #04100d;
}

#signal-meter::-webkit-progress-bar {
  border-radius: 999px;
  background: #04100d;
}

#signal-meter::-webkit-progress-value {
  border-radius: 999px;
  background: linear-gradient(90deg, var(--amber), var(--signal-strong));
  transition: width 80ms linear;
}

#signal-meter::-moz-progress-bar {
  border-radius: 999px;
  background: linear-gradient(90deg, var(--amber), var(--signal-strong));
}

.reception-result {
  position: relative;
  min-height: 104px;
  margin-top: 18px;
  padding: 14px 16px;
  border-left: 3px solid var(--line);
  background: rgba(2, 13, 10, 0.5);
}

.reception-result strong {
  color: var(--signal);
  font: 900 0.85rem/1.2 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.12em;
}

.reception-result p {
  margin: 5px 0 0;
  color: var(--muted);
}

.reception-result[data-result="lost"] {
  border-left-color: var(--danger);
}

.reception-result[data-result="lost"] strong {
  color: var(--danger);
}

.answer-reveal {
  color: var(--text) !important;
  font-weight: 800;
}

.replay-button {
  position: relative;
  width: 100%;
  margin-top: 14px;
}

.input-panel {
  padding: 18px 20px;
}

.input-panel label {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-weight: 800;
}

#typing-input {
  width: 100%;
  min-height: 58px;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 11px 14px;
  color: var(--text);
  background: #03100c;
  caret-color: var(--signal);
  font: 700 clamp(1.05rem, 3vw, 1.45rem)/1.35 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.04em;
}

#typing-input[aria-invalid="true"] {
  border-color: var(--danger);
  box-shadow: 0 0 0 3px rgba(255, 124, 112, 0.12);
}

#typing-input:disabled {
  color: #789087;
  background: #07110f;
  opacity: 1;
}

.input-feedback {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  margin-top: 9px;
}

.input-feedback p {
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
}

.input-feedback .mode-safety-note {
  text-align: right;
}

.result-panel,
.how-to,
.related-modes {
  margin-top: 20px;
  padding: 22px;
}

.result-panel {
  border-color: rgba(51, 233, 159, 0.55);
}

.result-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
}

.main-result {
  display: grid;
  grid-template-columns: auto auto;
  align-items: baseline;
  gap: 0 8px;
  margin: 0;
  text-align: right;
}

.main-result span {
  grid-column: 1 / -1;
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 800;
}

.main-result strong {
  color: var(--signal);
  font: 900 clamp(2rem, 6vw, 3.6rem)/1 ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.main-result small {
  color: var(--muted);
  font-weight: 800;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 8px;
  margin: 20px 0 14px;
}

.result-grid div {
  min-width: 0;
  padding: 11px 10px;
  border: 1px solid var(--line-soft);
  border-radius: 11px;
  background: rgba(2, 13, 10, 0.55);
  text-align: center;
}

.result-grid dt {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
}

.result-grid dd {
  margin: 3px 0 0;
  color: var(--text);
  font: 800 1rem/1.3 ui-monospace, "SFMono-Regular", Consolas, monospace;
}

#result-summary {
  color: var(--muted);
}

.how-to p {
  margin: 9px 0 0;
  color: var(--muted);
}

.how-to strong,
.how-to code {
  color: var(--signal);
}

.how-to code {
  padding: 1px 5px;
  border: 1px solid var(--line-soft);
  border-radius: 5px;
  background: #04110d;
}

.related-modes {
  display: grid;
  grid-template-columns: minmax(170px, 0.8fr) minmax(0, 2fr);
  gap: 18px;
}

.related-links {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.related-links a,
.mode-list-link {
  border: 1px solid var(--line-soft);
  border-radius: 11px;
  color: var(--text);
  background: rgba(2, 13, 10, 0.5);
  text-decoration: none;
}

.related-links a {
  display: block;
  padding: 10px 12px;
}

.related-links strong,
.related-links small {
  display: block;
}

.related-links small {
  margin-top: 2px;
  color: var(--muted);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.mode-list-link {
  grid-column: 1 / -1;
  justify-self: start;
  padding: 8px 12px;
  color: var(--signal);
  font-weight: 800;
}

.site-footer {
  padding: 24px 16px 36px;
  border-top: 1px solid var(--line-soft);
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 20px;
}

.site-footer a {
  color: var(--muted);
  text-decoration: none;
}

.site-footer a:hover,
.related-modes a:hover {
  color: var(--signal);
}

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

[hidden] {
  display: none !important;
}

@media (max-width: 760px) {
  .app-shell,
  .site-header {
    width: min(100% - 22px, 680px);
  }

  .app-shell {
    padding-top: 24px;
  }

  .mode-intro {
    align-items: center;
  }

  .channel-badge {
    min-width: 106px;
    padding: 10px 12px;
  }

  .channel-badge strong {
    font-size: 1.7rem;
  }

  .audio-check {
    grid-template-columns: 1fr;
  }

  .audio-controls {
    grid-template-columns: 1fr;
  }

  .audio-controls label {
    grid-column: auto;
  }

  .status-metrics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .input-feedback,
  .result-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  .input-feedback .mode-safety-note,
  .main-result {
    text-align: left;
  }

  .result-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .related-modes {
    grid-template-columns: 1fr;
  }

  .related-links {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 470px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }

  .mode-intro {
    align-items: flex-start;
  }

  .channel-badge {
    display: none;
  }

  .audio-check,
  .status-panel,
  .receiver,
  .input-panel,
  .result-panel,
  .how-to,
  .related-modes {
    border-radius: 14px;
    padding: 16px;
  }

  .status-head {
    align-items: stretch;
    flex-direction: column;
  }

  .status-actions {
    justify-content: stretch;
  }

  .status-actions button {
    flex: 1;
  }

  .status-metrics div {
    padding: 9px;
  }

  .status-metrics dd {
    font-size: 1rem;
  }

  .signal-display {
    min-height: 92px;
  }

  .waveform {
    height: 72px;
    gap: 5px;
    padding: 0 8px;
  }

  .reception-result {
    min-height: 116px;
  }

  .result-grid {
    grid-template-columns: 1fr 1fr;
  }

  .result-grid div:last-child {
    grid-column: 1 / -1;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
  }
}