:root {
  color-scheme: dark;
  --bg: #0f1118;
  --panel: #181b24;
  --panel-border: rgba(255, 255, 255, 0.08);
  --text: #eff2ff;
  --muted: #a9b0c7;
  --accent: #8b5cf6;
  --accent-strong: #6d28d9;
  --success: #34d399;
  --danger: #fb7185;
  --shadow: 0 20px 45px rgba(0, 0, 0, 0.28);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top, rgba(139, 92, 246, 0.16), transparent 32%),
    linear-gradient(180deg, #11131c 0%, #090b11 100%);
  color: var(--text);
}

button,
input {
  font: inherit;
}

.app-shell {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 32px 0 48px;
  display: grid;
  gap: 24px;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: 24px;
}

.hero-panel {
  display: grid;
  gap: 20px;
}

.eyebrow {
  margin: 0 0 8px;
  color: #c4b5fd;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.8rem;
  font-weight: 700;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 12px;
  font-size: clamp(2rem, 4vw, 3.5rem);
  line-height: 1.05;
}

.hero-copy,
.section-heading p,
.shortcut-card p,
.feedback,
li {
  color: var(--muted);
}

.video-form {
  display: grid;
  gap: 10px;
}

.video-form label,
.status-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: #d2d8ef;
}

.input-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.input-row input {
  flex: 1 1 320px;
  padding: 14px 16px;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
}

.input-row input:focus,
.input-row button:focus {
  outline: 2px solid rgba(139, 92, 246, 0.6);
  outline-offset: 2px;
}

.input-row button {
  padding: 14px 20px;
  border: 0;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: white;
  font-weight: 700;
  cursor: pointer;
}

.feedback {
  min-height: 1.3em;
  margin-bottom: 0;
}

.feedback.error {
  color: var(--danger);
}

.feedback.success {
  color: var(--success);
}

.section-heading {
  margin-bottom: 18px;
}

.section-heading h2 {
  margin-bottom: 6px;
}

.video-frame {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border-radius: 20px;
  background: #090b11;
}

.video-frame iframe,
.video-frame #youtube-player {
  width: 100%;
  height: 100%;
  border: 0;
}

.loop-controls {
  margin-top: 18px;
}

.loop-readout {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.loop-action-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 16px;
}

.loop-action-row button {
  padding: 12px 16px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
  cursor: pointer;
}

.loop-action-row button:hover {
  background: rgba(255, 255, 255, 0.09);
}

.loop-action-row button:focus {
  outline: 2px solid rgba(139, 92, 246, 0.6);
  outline-offset: 2px;
}

.loop-action-row button.active {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  border-color: transparent;
  color: white;
}

.status-grid,
.shortcut-grid {
  display: grid;
  gap: 16px;
}

.status-grid {
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  margin-bottom: 20px;
}

.status-card,
.shortcut-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.07);
  border-radius: 18px;
  padding: 16px;
}

.status-card strong {
  display: block;
  margin-top: 8px;
  font-size: 1.1rem;
}

.volume-control {
  margin-bottom: 18px;
  padding: 16px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.07);
}

.volume-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 10px;
}

.volume-row input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
}

.volume-row strong {
  min-width: 52px;
  text-align: right;
}

.piano {
  --white-key-width: min(11vw, 82px);
  position: relative;
  display: flex;
  align-items: flex-start;
  overflow-x: auto;
  padding: 16px 0 10px;
  margin-bottom: 22px;
}

.key {
  position: relative;
  border: 1px solid #0d0f17;
  border-radius: 0 0 12px 12px;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  user-select: none;
  transition: transform 120ms ease, background 120ms ease, box-shadow 120ms ease;
}

.key.white {
  width: var(--white-key-width);
  min-width: var(--white-key-width);
  height: 220px;
  margin-right: 2px;
  background: linear-gradient(180deg, #ffffff 0%, #dce1f7 100%);
  color: #111827;
}

.key.black {
  width: calc(var(--white-key-width) * 0.62);
  min-width: calc(var(--white-key-width) * 0.62);
  height: 138px;
  margin-left: calc(var(--white-key-width) * -0.31);
  margin-right: calc(var(--white-key-width) * -0.31);
  z-index: 2;
  background: linear-gradient(180deg, #353b4c 0%, #0f1118 100%);
  color: #eef2ff;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
}

.key.active {
  transform: translateY(2px);
  background: linear-gradient(180deg, #c4b5fd 0%, #7c3aed 100%);
  color: white;
  box-shadow: 0 0 0 2px rgba(196, 181, 253, 0.18);
}

.key-label {
  margin-bottom: 16px;
  font-size: 0.86rem;
  font-weight: 700;
}

.key.black .key-label {
  margin-bottom: 12px;
}

.shortcut-grid {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.shortcut-card ul {
  margin: 0;
  padding-left: 18px;
}

code {
  padding: 0.16rem 0.4rem;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
}

@media (max-width: 720px) {
  .app-shell {
    width: min(100% - 20px, 1120px);
    padding-top: 20px;
  }

  .panel {
    padding: 18px;
    border-radius: 18px;
  }

  .key.white {
    height: 180px;
  }

  .key.black {
    height: 116px;
  }

  .loop-action-row button {
    width: 100%;
  }

  .volume-row {
    align-items: stretch;
    flex-direction: column;
  }

  .volume-row strong {
    min-width: 0;
    text-align: left;
  }
}