:root {
  color-scheme: dark;
  --background: #070913;
  --surface: rgba(15, 20, 36, 0.78);
  --surface-strong: rgba(10, 13, 25, 0.94);
  --text: #f3f4f6;
  --muted: #9ca3af;
  --faint: #6b7280;
  --accent: #818cf8;
  --border: rgba(255, 255, 255, 0.11);
  --font-display: "Outfit", "Segoe UI", sans-serif;
  --font-body: "Inter", "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--background);
  color: var(--text);
  font-family: var(--font-body);
}

button,
a {
  font: inherit;
}

.sphere-stage {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background:
    radial-gradient(circle at 50% 48%, rgba(99, 102, 241, 0.10), transparent 44%),
    var(--background);
}

.sphere-stage::after {
  position: absolute;
  inset: 0;
  content: "";
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.012) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.012) 1px, transparent 1px);
  background-size: 4px 4px;
}

#symbol-sphere {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  cursor: grab;
  touch-action: none;
}

#symbol-sphere.is-dragging {
  cursor: grabbing;
}

.sphere-header {
  position: absolute;
  z-index: 2;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  padding: 24px 28px;
  pointer-events: none;
}

.sphere-header > * {
  pointer-events: auto;
}

.back-link {
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-decoration: none;
  text-transform: uppercase;
}

.back-link:hover,
.back-link:focus-visible {
  color: var(--text);
}

h1 {
  margin: 8px 0 2px;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 2.6vw, 2.2rem);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.sphere-header p {
  margin: 0;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
}

.sphere-actions {
  display: flex;
  gap: 8px;
}

.sphere-actions button,
.symbol-detail button {
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}

.sphere-actions button {
  padding: 9px 14px;
  font-size: 0.76rem;
}

.sphere-actions button:hover,
.sphere-actions button:focus-visible,
.symbol-detail button:hover,
.symbol-detail button:focus-visible {
  border-color: rgba(129, 140, 248, 0.65);
  background: rgba(99, 102, 241, 0.18);
  outline: none;
}

.loading-panel {
  position: absolute;
  z-index: 3;
  top: 50%;
  left: 50%;
  width: min(320px, calc(100% - 48px));
  padding: 18px;
  transform: translate(-50%, -50%);
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface-strong);
  color: var(--muted);
  font-size: 0.8rem;
  text-align: center;
  backdrop-filter: blur(14px);
  transition: opacity 240ms ease;
}

.loading-panel.is-complete {
  opacity: 0;
  pointer-events: none;
}

.loading-panel.is-error {
  color: #fca5a5;
}

.loading-track {
  display: block;
  height: 2px;
  margin-top: 13px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
}

#loading-progress {
  display: block;
  width: 0;
  height: 100%;
  background: var(--accent);
  transition: width 120ms linear;
}

.symbol-detail {
  position: absolute;
  z-index: 3;
  left: 50%;
  bottom: 58px;
  display: flex;
  align-items: center;
  min-width: 190px;
  padding: 10px 12px 10px 10px;
  transform: translateX(-50%);
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface-strong);
  backdrop-filter: blur(14px);
}

.symbol-detail[hidden] {
  display: none;
}

.symbol-detail img {
  width: 48px;
  height: 48px;
  margin-right: 12px;
  padding: 5px;
  border-radius: 9px;
  background: var(--text);
  object-fit: contain;
}

.detail-label {
  display: block;
  color: var(--muted);
  font-size: 0.66rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

#selected-symbol-id {
  display: block;
  margin-top: 2px;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: 0.08em;
}

.symbol-detail button {
  width: 28px;
  height: 28px;
  margin-left: auto;
  padding: 0;
  font-size: 1rem;
  line-height: 1;
}

.sphere-help {
  position: absolute;
  z-index: 2;
  right: 24px;
  bottom: 22px;
  left: 24px;
  display: flex;
  justify-content: center;
  gap: 22px;
  color: var(--faint);
  font-size: 0.7rem;
  letter-spacing: 0.03em;
  pointer-events: none;
}

.sphere-header,
.sphere-help,
.symbol-detail {
  transition: opacity 420ms ease;
}

.sphere-stage.is-ui-idle .sphere-header,
.sphere-stage.is-ui-idle .sphere-help,
.sphere-stage.is-ui-idle .symbol-detail {
  opacity: 0;
  pointer-events: none;
}

.sphere-stage.is-ui-idle #symbol-sphere {
  cursor: none;
}

@media (max-width: 640px) {
  .sphere-header {
    padding: 18px;
  }

  .sphere-actions {
    flex-direction: column;
  }

  .sphere-actions button {
    padding: 8px 11px;
  }

  .sphere-help {
    right: 12px;
    bottom: 12px;
    left: 12px;
    gap: 10px;
    font-size: 0.62rem;
    text-align: center;
  }

  .symbol-detail {
    bottom: 52px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .loading-panel,
  #loading-progress,
  .sphere-header,
  .sphere-help,
  .symbol-detail {
    transition: none;
  }
}