/* ─── RESET & BASE ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:      #0c0e18;
  --panel:   #131627;
  --panel2:  #1a1e35;
  --border:  #252942;
  --gold:    #c9a44a;
  --gold2:   #e8c46a;
  --text:    #e0e2f0;
  --muted:   #7880a0;
  --success: #4caf6e;
  --error:   #e05555;
  --key-w:   #f2ede6;
  --key-b:   #1a1a24;
  --radius:  10px;
  --fs:      15px;
}

html, body { height: 100%; font-family: -apple-system, 'Segoe UI', sans-serif; font-size: var(--fs); background: var(--bg); color: var(--text); }

/* ─── LOADING ───────────────────────────────────────────────────── */
#loading-overlay {
  position: fixed; inset: 0; background: var(--bg);
  display: flex; align-items: center; justify-content: center;
  z-index: 9999; transition: opacity .4s;
}
#loading-overlay.hidden { opacity: 0; pointer-events: none; }
.loading-inner { text-align: center; }
.loading-logo { font-size: 56px; color: var(--gold); animation: pulse 1.4s ease-in-out infinite; }
@keyframes pulse { 0%,100%{opacity:.4;transform:scale(.9)} 50%{opacity:1;transform:scale(1.1)} }
.loading-bar { width: 220px; height: 4px; background: var(--panel2); border-radius: 2px; margin: 20px auto 12px; overflow: hidden; }
.loading-fill { height: 100%; background: var(--gold); width: 0; transition: width .3s; border-radius: 2px; }
#loading-text { color: var(--muted); font-size: 13px; }

/* ─── SCREENS ───────────────────────────────────────────────────── */
.screen { display: none; min-height: 100vh; }
.screen.active { display: block; }

/* ─── HOME HEADER ───────────────────────────────────────────────── */
.home-header {
  background: linear-gradient(160deg, #131a38 0%, #0c0e18 70%);
  border-bottom: 1px solid var(--border);
  padding: 48px 24px 36px;
  text-align: center;
}
.rcm-badge {
  display: inline-block; background: var(--gold); color: #111;
  font-size: 11px; font-weight: 700; letter-spacing: .15em;
  padding: 3px 10px; border-radius: 4px; margin-bottom: 14px;
}
.home-header h1 { font-size: 36px; font-weight: 700; color: var(--text); letter-spacing: -.5px; }
.home-sub { color: var(--muted); margin-top: 6px; font-size: 14px; letter-spacing: .04em; }
.global-stats { display: flex; gap: 28px; justify-content: center; margin-top: 24px; }
.gstat { text-align: center; }
.gstat-val { font-size: 22px; font-weight: 700; color: var(--gold); }
.gstat-lbl { font-size: 11px; color: var(--muted); text-transform: uppercase; letter-spacing: .08em; margin-top: 2px; }

/* ─── MODULE GRID ───────────────────────────────────────────────── */
.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  padding: 28px 24px;
  max-width: 1100px;
  margin: 0 auto;
}
.module-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 20px;
  cursor: pointer;
  transition: border-color .2s, transform .15s, box-shadow .2s;
  display: flex; flex-direction: column; gap: 10px;
}
.module-card:hover { border-color: var(--gold); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,.4); }
.module-card-top { display: flex; align-items: center; gap: 12px; }
.module-icon { font-size: 28px; }
.module-name { font-size: 17px; font-weight: 600; }
.module-desc { font-size: 13px; color: var(--muted); line-height: 1.5; }
.module-score-bar { background: var(--panel2); border-radius: 3px; height: 5px; overflow: hidden; }
.module-score-fill { height: 100%; background: var(--gold); border-radius: 3px; transition: width .4s; }
.module-score-label { font-size: 12px; color: var(--muted); }

/* ─── HOME FOOTER ───────────────────────────────────────────────── */
.home-footer { text-align: center; padding: 0 0 36px; }
.btn-reset-all { background: none; border: 1px solid var(--border); color: var(--muted); padding: 8px 18px; border-radius: 6px; cursor: pointer; font-size: 13px; transition: border-color .2s, color .2s; }
.btn-reset-all:hover { border-color: var(--error); color: var(--error); }

/* ─── EXERCISE HEADER ───────────────────────────────────────────── */
.ex-header {
  display: flex; align-items: center; gap: 16px;
  padding: 14px 20px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 10;
}
.btn-back { background: none; border: none; color: var(--muted); cursor: pointer; font-size: 14px; padding: 4px 8px; border-radius: 4px; transition: color .2s; white-space: nowrap; }
.btn-back:hover { color: var(--text); }
.ex-header h2 { flex: 1; font-size: 18px; font-weight: 600; }
.ex-score { font-size: 14px; color: var(--gold); font-weight: 600; white-space: nowrap; min-width: 60px; text-align: right; }

/* ─── EXERCISE BODY ─────────────────────────────────────────────── */
#ex-body { max-width: 820px; margin: 0 auto; padding: 28px 20px 60px; }

/* ─── EXERCISE PROMPT ───────────────────────────────────────────── */
.ex-prompt {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 20px;
}
.ex-prompt-label { font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: .1em; margin-bottom: 8px; }
.ex-prompt-text { font-size: 20px; font-weight: 600; color: var(--text); }
.ex-prompt-sub { font-size: 14px; color: var(--muted); margin-top: 6px; }

/* ─── PLAY CONTROLS ─────────────────────────────────────────────── */
.play-controls { display: flex; gap: 12px; margin-bottom: 24px; flex-wrap: wrap; }
.btn-play {
  background: var(--gold); color: #111;
  border: none; border-radius: 8px;
  padding: 12px 28px; font-size: 15px; font-weight: 700;
  cursor: pointer; transition: background .2s, transform .1s;
  display: flex; align-items: center; gap: 8px;
}
.btn-play:hover { background: var(--gold2); transform: translateY(-1px); }
.btn-play:active { transform: translateY(0); }
.btn-play:disabled { opacity: .5; cursor: not-allowed; transform: none; }
.btn-play-again {
  background: var(--panel2); border: 1px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 12px 20px; font-size: 14px; cursor: pointer;
  transition: border-color .2s;
}
.btn-play-again:hover { border-color: var(--gold); }
.btn-play-again:disabled { opacity: .4; cursor: not-allowed; }

/* ─── PIANO KEYBOARD ────────────────────────────────────────────── */
.keyboard-wrap { overflow-x: auto; padding-bottom: 12px; margin-bottom: 20px; }
.piano-keyboard { position: relative; display: inline-flex; }
.keys-white { display: flex; }
.key-white {
  width: 40px; height: 130px;
  background: var(--key-w);
  border: 1px solid #999;
  border-radius: 0 0 5px 5px;
  position: relative;
  flex-shrink: 0;
  transition: background .1s;
  cursor: default;
}
.key-white.clickable { cursor: pointer; }
.key-white.clickable:hover { background: #ddeeff; }
.key-white.playing { background: var(--gold) !important; }
.key-white.hl-root { background: #f0a030 !important; }
.key-white.hl-note { background: #5bc4f0 !important; }
.key-white.hl-correct { background: var(--success) !important; }
.key-white.hl-wrong { background: var(--error) !important; }
.key-white.hl-input { background: #8080e0 !important; }
.key-label { position: absolute; bottom: 5px; left: 0; right: 0; text-align: center; font-size: 9px; color: #777; }

.keys-black { position: absolute; top: 0; left: 0; pointer-events: none; }
.key-black {
  position: absolute;
  width: 26px; height: 80px;
  background: var(--key-b);
  border-radius: 0 0 4px 4px;
  pointer-events: auto;
  transition: background .1s;
  cursor: default;
  z-index: 2;
}
.key-black.clickable { cursor: pointer; }
.key-black.clickable:hover { background: #3344aa; }
.key-black.playing { background: var(--gold) !important; }
.key-black.hl-root { background: #c07820 !important; }
.key-black.hl-note { background: #1a80b0 !important; }
.key-black.hl-correct { background: #2a8a4a !important; }
.key-black.hl-wrong { background: #a02020 !important; }
.key-black.hl-input { background: #5050c0 !important; }

/* ─── ANSWER BUTTONS ────────────────────────────────────────────── */
.answer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 10px;
  margin-bottom: 20px;
}
.answer-grid.wide { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
.answer-grid.narrow { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); }
.btn-answer {
  background: var(--panel2); border: 1.5px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 13px 12px; font-size: 14px; font-weight: 500;
  cursor: pointer; transition: border-color .15s, background .15s;
  text-align: center; line-height: 1.3;
}
.btn-answer:hover:not(:disabled) { border-color: var(--gold); background: #1e2240; }
.btn-answer.correct { border-color: var(--success); background: rgba(76,175,110,.15); color: var(--success); }
.btn-answer.wrong { border-color: var(--error); background: rgba(224,85,85,.12); color: var(--error); }
.btn-answer.reveal { border-color: var(--success); background: rgba(76,175,110,.08); }
.btn-answer:disabled { cursor: default; }

/* ─── FEEDBACK ──────────────────────────────────────────────────── */
.feedback {
  background: var(--panel);
  border-radius: var(--radius);
  border-left: 4px solid var(--border);
  padding: 16px 20px;
  margin-bottom: 20px;
  display: none;
}
.feedback.correct { border-color: var(--success); }
.feedback.wrong { border-color: var(--error); }
.feedback-title { font-weight: 700; font-size: 16px; margin-bottom: 4px; }
.feedback.correct .feedback-title { color: var(--success); }
.feedback.wrong .feedback-title { color: var(--error); }
.feedback-body { font-size: 14px; color: var(--muted); line-height: 1.5; }

/* ─── NEXT BUTTON ───────────────────────────────────────────────── */
.btn-next {
  background: var(--gold); color: #111; border: none; border-radius: 8px;
  padding: 13px 36px; font-size: 15px; font-weight: 700;
  cursor: pointer; display: none; transition: background .2s;
}
.btn-next:hover { background: var(--gold2); }
.btn-next.visible { display: inline-block; }

/* ─── RHYTHM MODULE ─────────────────────────────────────────────── */
.rhythm-display {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}
.rhythm-info { font-size: 13px; color: var(--muted); margin-bottom: 14px; }
.beat-grid { display: flex; gap: 4px; flex-wrap: wrap; }
.beat-row { display: flex; gap: 4px; align-items: center; margin-bottom: 8px; width: 100%; }
.beat-label { font-size: 12px; color: var(--muted); width: 32px; text-align: right; flex-shrink: 0; }
.beat-cell {
  width: 36px; height: 36px; border-radius: 5px;
  border: 1.5px solid var(--border); background: var(--panel2);
  cursor: pointer; transition: background .1s, border-color .1s;
  flex-shrink: 0; position: relative;
}
.beat-cell.subdivision { opacity: .6; }
.beat-cell.beat-on { background: var(--gold); border-color: var(--gold); }
.beat-cell.beat-on.subdivision { background: #7a6020; border-color: #7a6020; }
.beat-cell.correct { background: var(--success); border-color: var(--success); }
.beat-cell.wrong-extra { background: var(--error); border-color: var(--error); }
.beat-cell.wrong-missing { background: #662020; border-color: var(--error); border-style: dashed; }
.beat-cell.playing-now { box-shadow: 0 0 0 3px var(--gold); }
.beat-sep { width: 1px; height: 36px; background: var(--border); flex-shrink: 0; }
.tap-btn {
  background: var(--panel2); border: 2px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 14px 32px; font-size: 15px; font-weight: 600;
  cursor: pointer; transition: all .1s; user-select: none;
}
.tap-btn:active { background: var(--gold); border-color: var(--gold); color: #111; transform: scale(.96); }

/* ─── MELODY MODULE ─────────────────────────────────────────────── */
.melody-input-area { margin-bottom: 20px; }
.melody-sequence {
  display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 16px; min-height: 48px;
  padding: 12px 16px; background: var(--panel); border: 1px solid var(--border); border-radius: 8px;
  align-items: center;
}
.melody-note-chip {
  background: var(--panel2); border: 1px solid var(--border);
  border-radius: 6px; padding: 6px 12px; font-size: 14px; font-weight: 600;
}
.melody-note-chip.correct { border-color: var(--success); color: var(--success); background: rgba(76,175,110,.1); }
.melody-note-chip.wrong { border-color: var(--error); color: var(--error); background: rgba(224,85,85,.1); }
.melody-note-chip.current { border-color: var(--gold); color: var(--gold); }
.melody-empty { color: var(--muted); font-size: 14px; font-style: italic; }
.btn-clear-melody {
  background: none; border: 1px solid var(--border); color: var(--muted);
  border-radius: 6px; padding: 6px 14px; font-size: 13px; cursor: pointer;
  transition: border-color .2s, color .2s;
}
.btn-clear-melody:hover { border-color: var(--error); color: var(--error); }
.melody-controls { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.melody-counter { font-size: 13px; color: var(--muted); }

/* ─── PROGRESSION MODULE ────────────────────────────────────────── */
.progression-slots { display: flex; gap: 10px; margin-bottom: 20px; flex-wrap: wrap; }
.prog-slot {
  flex: 1; min-width: 80px;
  background: var(--panel); border: 1.5px solid var(--border);
  border-radius: 8px; padding: 16px 10px; text-align: center;
}
.prog-slot-num { font-size: 11px; color: var(--muted); margin-bottom: 6px; }
.prog-slot-answer { font-size: 22px; font-weight: 700; min-height: 32px; color: var(--text); }
.prog-slot.filled { border-color: var(--gold); }
.prog-slot.correct { border-color: var(--success); }
.prog-slot.wrong { border-color: var(--error); }
.prog-slot.correct .prog-slot-answer { color: var(--success); }
.prog-slot.wrong .prog-slot-answer { color: var(--error); }
.prog-rn-grid { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px; }
.btn-rn {
  background: var(--panel2); border: 1.5px solid var(--border); color: var(--text);
  border-radius: 6px; padding: 10px 14px; font-size: 15px; font-weight: 600;
  cursor: pointer; font-family: serif; transition: border-color .15s, background .15s;
}
.btn-rn:hover:not(:disabled) { border-color: var(--gold); background: #1e2240; }
.btn-rn.selected { border-color: var(--gold); background: rgba(201,164,74,.15); }
.prog-slot-select-indicator { font-size: 11px; color: var(--gold); margin-top: 4px; height: 14px; }

/* ─── CADENCE MODULE ────────────────────────────────────────────── */
.cadence-desc { font-size: 13px; color: var(--muted); line-height: 1.6; margin-top: 6px; }
.key-chip {
  display: inline-block; background: var(--panel2); border: 1px solid var(--border);
  border-radius: 4px; padding: 2px 8px; font-size: 12px; color: var(--gold); margin-left: 4px;
}

/* ─── SECTION TAGS ──────────────────────────────────────────────── */
.section-tag {
  font-size: 11px; font-weight: 700; text-transform: uppercase;
  letter-spacing: .1em; color: var(--muted); margin-bottom: 8px;
}

/* ─── DIVIDER ───────────────────────────────────────────────────── */
.divider { height: 1px; background: var(--border); margin: 20px 0; }

/* ─── RESPONSIVE ────────────────────────────────────────────────── */
@media (max-width: 600px) {
  .home-header { padding: 32px 16px 24px; }
  .home-header h1 { font-size: 28px; }
  .module-grid { padding: 16px; gap: 12px; }
  #ex-body { padding: 16px 12px 48px; }
  .answer-grid { grid-template-columns: 1fr 1fr; }
  .key-white { width: 32px; height: 110px; }
  .key-black { width: 21px; height: 65px; }
}