/* =========================================================================
 * Piano Hero — page-specific styles.
 *
 * The shared /play/style.css + /play/piano/style.css imports give us the
 * full instrument-page chrome (header, controls bar, keyboard) and the
 * piano-keyboard component. This file just adds:
 *   - the falling-notes canvas, stacked above the keyboard
 *   - the fullscreen drag-and-drop overlay
 *   - a tweaked piano-stage (vertical layout: canvas on top, keyboard below)
 *   - small toolbar buttons for Pick-a-song / Play / Restart
 * Everything else flows from the shared family chrome.
 * ========================================================================= */

/* The shared `.instrument-body` rule is `min-height: 100vh`, which on a
 * standard "free play" instrument page is fine — the page can scroll if
 * help text + keyboard run long. Piano Hero is different: the falling-
 * notes canvas needs to sit directly above the keyboard, and the keyboard
 * itself must always be visible (it's the target the notes fall onto).
 *
 * Lock the body to viewport height so chrome + stage always fit, the
 * keyboard pins to the bottom, and the canvas takes the rest. The inline
 * `.instrument-help` panel is hidden in favour of the shared `?`
 * help-popup (loaded by /play/shared/help-popup.js) — that mechanism
 * already exists for phones and we just promote it to all viewports
 * here so the keyboard never gets pushed off-screen by a help block. */
.piano-hero-body {
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
  padding-bottom: 0;
}

.piano-hero-body .instrument-help {
  display: none;
}

/* The shared `.piano-stage` rule is `display: flex; align-items: center;`
 * which centers a single keyboard. We need a vertical stack: canvas on
 * top (fills remaining height), keyboard pinned to the bottom. */
.piano-hero-stage {
  flex-direction: column;
  align-items: stretch;
  justify-content: flex-end;
  gap: 8px;
  padding: 12px;
  flex: 1 1 0;
  /* Allow this flex child to shrink below its content's intrinsic height
   * inside the body's locked 100dvh box — without `min-height: 0` the
   * canvas's intrinsic size would push the keyboard off the bottom. */
  min-height: 0;
  position: relative;
}

#note-stage {
  flex: 1 1 0;
  width: 100%;
  /* No hard min-height: on short viewports the canvas yields space to
   * the keyboard rather than pushing the page past 100dvh. The renderer
   * is happy with whatever vertical room it gets — falling-note speed is
   * derived from canvas height at draw time. */
  min-height: 0;
  display: block;
  background: linear-gradient(
    180deg,
    color-mix(in srgb, var(--surface-2) 80%, transparent),
    color-mix(in srgb, var(--surface-0) 90%, transparent)
  );
  border-radius: 14px;
  border: 1px solid var(--border);
  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--pure-white) 4%, transparent);
}

/* The reused keyboard component pads itself with 14px on each side and
 * has `width: min(100%, 1100px)`. The note-stage canvas above must visually
 * line up with the keys — the renderer queries each key's getBoundingClientRect
 * so the alignment is automatic regardless of width. */
.piano-hero-stage .piano-keyboard {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  flex: 0 0 auto;
}

/* Promote the shared "?" help-popup trigger to all viewports on this
 * page (the default rule in /play/styles/help-popup.css only shows it on
 * phones). The inline `.instrument-help` is hidden above, so the popup
 * is the only way to read the instructions on desktop too. */
.piano-hero-body .help-popup-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  /* Sit just left of the "Piano" instruments pill in the header, with a
   * 6px gap so the cluster reads as one control group. */
  top: 14px;
  right: 110px;
}

@media (max-width: 720px), (max-height: 540px) {
  .piano-hero-body .help-popup-button {
    /* Fall back to the shared mobile placement (top: 6, right: 50). */
    top: 6px;
    right: 50px;
  }
}

/* ---------- Toolbar ----------------------------------------------------- */

.ph-primary-button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius);
  background: var(--accent-primary-bg);
  color: var(--text-on-accent);
  border: 1px solid var(--accent-primary-bg);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: background 200ms ease, transform 200ms ease;
}

.ph-primary-button:hover,
.ph-primary-button:focus-visible {
  background: var(--accent-primary-bg-hover);
  border-color: var(--accent-primary-bg-hover);
  transform: translateY(-1px);
  outline: none;
}

.ph-control-button {
  background: var(--surface-1);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 120ms ease, background 120ms ease;
  min-width: 64px;
}

.ph-control-button:hover:not([disabled]),
.ph-control-button:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.ph-control-button[disabled] {
  opacity: 0.4;
  cursor: not-allowed;
}

/* ---------- Drag-and-drop overlay -------------------------------------- */

/* The drop overlay covers the whole viewport while a file is being
 * dragged over the page. file-loader.js toggles `.dragging` on
 * <body> when a dragenter that contains files fires, and clears it on
 * dragleave/drop. */
.piano-hero-drop-overlay {
  position: fixed;
  inset: 0;
  z-index: 999990;
  display: none;
  align-items: center;
  justify-content: center;
  background: color-mix(in srgb, var(--surface-2) 75%, transparent);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  pointer-events: none;
  font-family: var(--font-display, var(--font-sans));
}

.piano-hero-body.dragging .piano-hero-drop-overlay {
  display: flex;
}

.piano-hero-drop-overlay .drop-card {
  border: 2px dashed var(--accent);
  border-radius: 16px;
  padding: 32px 48px;
  background: color-mix(in srgb, var(--surface-0) 70%, transparent);
  color: var(--fg);
  text-align: center;
  box-shadow: 0 24px 60px -20px color-mix(in srgb, var(--pure-black) 60%, transparent);
}

.piano-hero-drop-overlay .drop-icon {
  font-size: 48px;
  line-height: 1;
  margin-bottom: 12px;
}

.piano-hero-drop-overlay .drop-title {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 6px;
}

.piano-hero-drop-overlay .drop-sub {
  font-size: 14px;
  color: var(--fg-dim);
}

/* ---------- Mobile -------------------------------------------------------
 *
 * Below 720px (matches the shared keyboard mobile breakpoint), tighten the
 * controls bar so the toolbar wraps cleanly and the falling-notes canvas
 * doesn't get crushed. */
@media (max-width: 720px), (max-height: 540px) {
  .piano-hero-stage {
    padding: 8px;
    gap: 6px;
  }

  #note-stage {
    min-height: 160px;
    border-radius: 10px;
  }

  .ph-primary-button {
    padding: 7px 14px;
    font-size: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .ph-primary-button,
  .ph-control-button {
    transition: none !important;
  }
  .ph-primary-button:hover {
    transform: none !important;
  }
}