/* A screen you can read across a room and operate without looking at it:
   one big title, one artist line, one hairline of progress. */

:root {
  --bg: #0a0a0b;
  --text: #f4f4f5;
  --muted: #7c7c85;
  --dim: #46464e;
  --accent: #f4f4f5;
  --gap: clamp(1.5rem, 5vw, 3rem);
}

* {
  box-sizing: border-box;
}

/* The classes below set display, which would otherwise out-specify the
   browser's own [hidden] rule and leave hidden elements on screen. */
[hidden] {
  display: none !important;
}

html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
    system-ui, sans-serif;
  /* No text selection or long-press callout: every tap here is a transport
     control, not a chance to select a word. */
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior: none;
}

.stage {
  /* dvh rather than vh: on iOS Safari vh is the *largest* viewport, so a 100vh
     layout hides its bottom row behind the browser chrome. */
  min-height: 100dvh;
  display: grid;
  grid-template-rows: 1fr auto;
  align-items: center;
  padding: calc(var(--gap) + env(safe-area-inset-top)) var(--gap)
    calc(var(--gap) + env(safe-area-inset-bottom));
  /* The stage owns horizontal drags, so the browser must not read a skip
     swipe as a scroll or a page-back. */
  touch-action: none;
  transition: opacity 160ms ease, transform 160ms ease;
}

/* --- empty state --- */

.empty {
  max-width: 34rem;
  margin: 0 auto;
  text-align: center;
}

.empty-title {
  margin: 0 0 0.75rem;
  font-size: clamp(2rem, 7vw, 3rem);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.empty-copy {
  margin: 0 0 2rem;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.5;
}

.picker {
  display: inline-block;
  padding: 0.85rem 1.6rem;
  border: 1px solid var(--dim);
  border-radius: 999px;
  color: var(--text);
  font-size: 1rem;
  cursor: pointer;
  transition: border-color 160ms ease, background-color 160ms ease;
}

.picker:hover {
  border-color: var(--muted);
  background: rgba(255, 255, 255, 0.04);
}

.picker input {
  /* Hidden but still clickable through the label wrapping it. */
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.pickers {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

/* The secondary route, shown only where folder picking is also on offer. */
.picker-alt {
  border-color: transparent;
  color: var(--muted);
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
}

.picker-alt:hover {
  border-color: var(--dim);
  background: transparent;
}

/* --- now playing --- */

.now {
  max-width: 48rem;
  margin: 0 auto;
  width: 100%;
  text-align: center;
}

.artist {
  margin: 0 0 0.6rem;
  color: var(--muted);
  font-size: clamp(0.95rem, 2.5vw, 1.15rem);
  font-weight: 500;
  letter-spacing: 0.01em;
}

.title {
  margin: 0 0 clamp(2rem, 7vh, 3.5rem);
  font-size: clamp(2rem, 9vw, 4.5rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.025em;
  /* Long titles wrap rather than overflowing, but never past three lines. */
  overflow-wrap: anywhere;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* Paused reads as a dimmed screen, so a glance answers "is it playing?" */
.stage.is-paused .title,
.stage.is-paused .artist {
  opacity: 0.45;
}

.progress {
  /* Generous hit area around a hairline: the bar is 3px, the target is 44. */
  padding: 1.25rem 0;
  margin: -1.25rem 0;
  cursor: pointer;
  touch-action: none;
}

.progress-track {
  height: 3px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.12);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 999px;
  /* Driven by scaleX from JS — far cheaper than animating width, since it
     never triggers layout. */
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 180ms linear;
}

.times {
  display: flex;
  justify-content: space-between;
  margin-top: 0.7rem;
  color: var(--dim);
  font-size: 0.8rem;
  font-variant-numeric: tabular-nums;
}

/* --- footer --- */

.foot {
  text-align: center;
  min-height: 2.5rem;
}

.status,
.hint {
  margin: 0;
  font-size: 0.8rem;
  color: var(--dim);
}

.hint {
  margin-top: 0.35rem;
  color: var(--muted);
}

/* --- skip feedback --- */

/* A swipe should register in the corner of your eye without needing a look. */
.stage.flash-next {
  animation: nudge-left 200ms ease;
}

.stage.flash-back {
  animation: nudge-right 200ms ease;
}

@keyframes nudge-left {
  50% {
    transform: translateX(-10px);
    opacity: 0.75;
  }
}

@keyframes nudge-right {
  50% {
    transform: translateX(10px);
    opacity: 0.75;
  }
}

@media (prefers-reduced-motion: reduce) {
  .stage.flash-next,
  .stage.flash-back {
    animation: none;
  }

  .progress-fill {
    transition: none;
  }
}