:root{
  --bg-void:#0B0B0A;
  --bg-surface:#131211;
  --text-primary:#F2EFE9;
  --text-muted:#A79F91;
  --text-faint:#6E685C;
  --accent-blue:#2E8EFF;
  --accent-blue-dim:#1B4A80;
  --hairline:rgba(242,239,233,0.14);
  --good:#4CD98A;
  --bad:#E0637A;
}
*{margin:0;padding:0;box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html,body{
  height:100%;
  background:var(--bg-void);
  color:var(--text-primary);
  font-family:'Jost',sans-serif;
  overscroll-behavior:none;
  overflow-x:hidden;
}
:lang(ko){ word-break:keep-all; }
body{ overflow-wrap:break-word; }
button{ font-family:inherit;touch-action:manipulation; }

/* ---- top nav ---- */
.topnav{
  display:flex;align-items:center;justify-content:space-between;
  padding:18px 20px;
  max-width:480px;margin:0 auto;
  padding-top:calc(18px + env(safe-area-inset-top));
}
.brand{ display:flex;align-items:center;gap:10px;text-decoration:none;transition:opacity .25s; }
.brand:hover{ opacity:0.8; }
.brand img{ width:24px;height:24px;flex-shrink:0; }
.brand-text{ display:flex;flex-direction:column;gap:2px; }
.brand-text span{
  font-family:'Jost',sans-serif;font-size:11px;font-weight:500;letter-spacing:0.14em;
  color:var(--text-primary);white-space:nowrap;
}
.brand-app-sub{
  font-size:8.5px !important;letter-spacing:0.16em !important;
  color:var(--accent-blue) !important;font-weight:400 !important;
}
.nav-right{ display:flex;align-items:center;gap:14px; }

.lang-select{ position:relative; }
.lang-current{
  background:none;border:1px solid var(--hairline);border-radius:50%;
  width:30px;height:30px;display:flex;align-items:center;justify-content:center;
  font-size:14px;line-height:1;cursor:pointer;transition:border-color .25s;
}
.lang-current:hover{ border-color:var(--accent-blue); }
.flag-icon{ width:20px;height:15px;object-fit:cover;border-radius:2px;display:block; }
.lang-dropdown button .flag-icon{ flex-shrink:0; }
.lang-dropdown{
  position:absolute;top:calc(100% + 10px);right:0;
  background:var(--bg-surface);border:1px solid var(--hairline);
  min-width:140px;padding:6px;display:flex;flex-direction:column;
  opacity:0;visibility:hidden;transform:translateY(-6px);
  transition:opacity .2s, transform .2s, visibility .2s;z-index:250;
}
.lang-dropdown.open{ opacity:1;visibility:visible;transform:translateY(0); }
.lang-dropdown button{
  display:flex;align-items:center;gap:9px;background:none;border:none;cursor:pointer;
  padding:9px 10px;font-family:'Jost',sans-serif;font-size:11.5px;color:var(--text-muted);text-align:left;
  transition:background .2s, color .2s;
}
.lang-dropdown button:hover{ background:var(--bg-void);color:var(--text-primary); }
.lang-dropdown button.active{ color:var(--accent-blue); }

.nav-burger{
  display:flex;align-items:center;justify-content:center;
  background:none;border:none;color:var(--text-primary);
  font-size:17px;cursor:pointer;padding:4px 6px;position:relative;
}
.nav-mobile-panel{
  display:flex;flex-direction:column;gap:22px;
  position:fixed;top:0;right:0;
  width:min(260px, 78vw);height:100vh;height:100dvh;
  background:var(--bg-surface);border-left:1px solid var(--hairline);
  z-index:300;padding:90px 28px 28px;
  transform:translateX(100%);transition:transform .35s ease;pointer-events:none;
}
.nav-mobile-panel.open{ transform:translateX(0); pointer-events:auto; }
.panel-link{
  display:block;background:none;border:none;text-align:left;
  font-family:'Jost',sans-serif;font-size:13px;letter-spacing:0.1em;
  color:var(--text-primary);cursor:pointer;text-decoration:none;padding:0;
}
.nav-panel-tools{
  display:flex;flex-direction:column;gap:16px;
  padding-top:20px;margin-top:-4px;
  border-top:1px solid var(--hairline);
}
.nav-panel-tools-label{
  font-family:'Jost',sans-serif;font-size:9.5px;letter-spacing:0.24em;
  color:var(--text-faint);
}
.nav-panel-tools .panel-link{
  font-size:11.5px !important;color:var(--text-muted) !important;
}
.nav-panel-close{
  position:absolute;top:26px;right:26px;background:none;border:none;
  color:var(--text-faint);font-size:15px;cursor:pointer;padding:6px;
}
.nav-panel-close:hover{ color:var(--accent-blue); }

/* ---- app shell ---- */
.app{
  min-height:calc(100vh - 64px);min-height:calc(100dvh - 64px);
  display:flex;flex-direction:column;
  padding-bottom:calc(20px + env(safe-area-inset-bottom));
  padding-left:env(safe-area-inset-left);padding-right:env(safe-area-inset-right);
  max-width:480px;margin:0 auto;
}

/* ---- tabbar ---- */
.tabbar{ display:flex;gap:6px;padding:6px 20px 0; }
.tab{
  flex:1;background:none;border:1px solid var(--hairline);color:var(--text-faint);
  padding:11px 0;font-size:9.5px;letter-spacing:0.06em;font-weight:500;
  cursor:pointer;transition:border-color .25s, color .25s, background .25s;white-space:nowrap;
}
.tab.active{ border-color:var(--accent-blue);color:var(--accent-blue);background:rgba(46,142,255,0.06); }

/* ---- screens ---- */
.screen{ display:none;flex:1;flex-direction:column;align-items:center;padding:26px 20px 20px;gap:16px; }
.screen.active{ display:flex; }
.row-label{ display:block;font-size:10px;letter-spacing:0.16em;color:var(--text-faint);margin-bottom:10px;text-align:center; }

/* ---- shared tempo controls (metronome + drum) ---- */
.bpm-display, .drum-bpm-display{ display:flex;align-items:baseline;gap:8px; }
.bpm-input{
  font-family:'Fraunces',serif;font-weight:500;font-size:68px;line-height:1;
  color:var(--text-primary);background:none;border:none;outline:none;
  width:3.6ch;min-width:3.6ch;text-align:right;-moz-appearance:textfield;
  padding:0 2px;
}
.bpm-input::-webkit-outer-spin-button,
.bpm-input::-webkit-inner-spin-button{ -webkit-appearance:none;margin:0; }
.bpm-input:focus{ color:var(--accent-blue); }
.bpm-unit{ font-size:12px;letter-spacing:0.16em;color:var(--text-faint); }

.bpm-slider-wrap{ display:flex;align-items:center;gap:14px;width:100%; }
.stepper{
  width:36px;height:36px;flex-shrink:0;border-radius:50%;
  border:1px solid var(--hairline);background:none;color:var(--text-primary);
  font-size:19px;cursor:pointer;transition:border-color .25s;
}
.stepper:hover{ border-color:var(--accent-blue); }

input[type="range"]{ flex:1;-webkit-appearance:none;height:2px;background:var(--hairline);outline:none; }
input[type="range"]::-webkit-slider-thumb{
  -webkit-appearance:none;width:18px;height:18px;border-radius:50%;
  background:var(--accent-blue);cursor:pointer;box-shadow:0 0 8px rgba(46,142,255,0.5);
}
input[type="range"]::-moz-range-thumb{
  width:18px;height:18px;border-radius:50%;border:none;background:var(--accent-blue);cursor:pointer;
}

.tap-tempo{
  background:none;border:1px solid var(--hairline);color:var(--text-muted);
  padding:11px 22px;font-size:10.5px;letter-spacing:0.14em;cursor:pointer;
  transition:border-color .25s, color .25s;
  touch-action:manipulation; /* prevents double-tap-to-zoom on rapid tapping */
  -webkit-user-select:none;user-select:none;
}
.tap-tempo:active{ border-color:var(--accent-blue);color:var(--accent-blue); }

.reset-btn-prominent{
  width:38px;height:38px;flex-shrink:0;border-radius:50%;
  border:1px solid var(--hairline);background:var(--bg-void);color:var(--accent-blue);
  display:flex;align-items:center;justify-content:center;cursor:pointer;
  box-shadow:0 4px 16px rgba(46,142,255,0.22);
  transition:transform .15s, border-color .2s;
}
.reset-btn-prominent:hover{ border-color:var(--accent-blue); }
.reset-btn-prominent:active{ transform:scale(0.92) rotate(-25deg); }
.reset-btn-prominent svg{ width:18px;height:18px; }
.seq-header-row{ width:100%;display:flex;align-items:center;justify-content:space-between; }
.seq-header-right{ display:flex;align-items:center;gap:16px; }
.history-block{ display:flex;align-items:center;gap:8px; }
.history-label{ font-family:'Jost',sans-serif;font-size:8.5px;letter-spacing:0.1em;color:var(--text-faint); }
.history-dots{ display:flex;gap:8px; }
.history-dot{
  width:13px;height:13px;border-radius:50%;
  border:1px solid var(--hairline);background:none;cursor:pointer;padding:0;
  transition:border-color .2s, background .2s, transform .15s;
}
.history-dot.filled{ background:var(--accent-blue-dim);border-color:var(--accent-blue); }
.history-dot.filled:hover{ background:var(--accent-blue);transform:scale(1.25);box-shadow:0 0 8px rgba(46,142,255,0.6); }
@keyframes historySavedPulse{
  0%{ background:var(--accent-blue-dim); box-shadow:0 0 0 rgba(46,142,255,0); transform:scale(1); }
  35%{ background:var(--accent-blue); box-shadow:0 0 14px rgba(46,142,255,0.9); transform:scale(1.5); }
  100%{ background:var(--accent-blue-dim); box-shadow:0 0 0 rgba(46,142,255,0); transform:scale(1); }
}
.history-dot.just-saved{ animation:historySavedPulse .7s ease-out; border-color:var(--accent-blue); }
.history-dot:not(.filled){ cursor:default; }
.history-hint{ font-size:10px;color:var(--text-faint);text-align:center;line-height:1.6;max-width:300px; }
.reset-hint{ font-size:10.5px;color:var(--text-faint);text-align:center;line-height:1.6;max-width:280px; }

.time-sig-row, .subdivision-row, .string-refs, .instrument-row{ width:100%; }
.chip-group{ display:flex;gap:8px;justify-content:center;flex-wrap:wrap; }
.chip{
  min-width:38px;padding:9px 11px;border:1px solid var(--hairline);background:none;
  color:var(--text-faint);font-size:12.5px;letter-spacing:0.03em;cursor:pointer;
  transition:border-color .2s, color .2s;display:flex;align-items:center;justify-content:center;
}
.chip.selected{ border-color:var(--accent-blue);color:var(--accent-blue); }
.chip.swing-letter{ font-family:'Fraunces',serif;font-style:italic;font-size:16px;min-width:38px; }
.chip.small-chip{ font-size:9.5px;padding:7px 10px;min-width:auto;letter-spacing:0.04em; }
.note-triplet-chip{ padding:9px 9px; }

.play-btn{
  width:70px;height:70px;border-radius:50%;background:var(--accent-blue);border:none;color:#04070C;
  display:flex;align-items:center;justify-content:center;cursor:pointer;margin-top:auto;
  box-shadow:0 8px 30px rgba(46,142,255,0.3);transition:transform .15s;flex-shrink:0;
}
.play-btn:active{ transform:scale(0.94); }
.play-btn svg{ width:26px;height:26px; }
.play-btn.playing{ background:var(--text-primary); }
.play-btn.small{ width:52px;height:52px; }
.play-btn.small svg{ width:19px;height:19px; }

/* ---- metronome beat row ---- */
.beat-row{ display:flex;gap:14px;justify-content:center;min-height:22px;flex-wrap:wrap; }
.beat-dot{
  width:15px;height:15px;border-radius:50%;border:1px solid var(--hairline);
  background:transparent;transition:background .08s, border-color .08s, transform .08s;
}
.beat-dot.on{ background:var(--accent-blue);border-color:var(--accent-blue);transform:scale(1.25);box-shadow:0 0 12px rgba(46,142,255,0.6); }
.beat-dot.accent.on{ background:var(--text-primary);border-color:var(--text-primary);box-shadow:0 0 14px rgba(242,239,233,0.7); }

/* ---- drum machine ---- */
.drum-top-row{ width:100%;display:flex;align-items:center;justify-content:center;gap:30px; }

.seq-grid{ width:100%;display:flex;flex-direction:column;gap:6px;overflow-x:auto; }
.seq-track{ display:grid;grid-template-columns:44px repeat(16, minmax(16px,1fr));gap:3px;align-items:center; }
.seq-track-label{ font-size:9px;letter-spacing:0.04em;color:var(--text-faint);text-align:right;padding-right:6px;white-space:nowrap; }
.seq-cell{
  aspect-ratio:1/1;border:1px solid var(--hairline);background:none;
  cursor:pointer;transition:background .12s, border-color .12s;min-width:14px;
}
.seq-cell:nth-child(4n+2){ margin-left:4px; }
.seq-cell.on{ background:var(--accent-blue);border-color:var(--accent-blue); }
.seq-cell.playhead{ border-color:var(--text-primary); }
.seq-cell.on.playhead{ background:var(--text-primary);border-color:var(--text-primary); }

.swing-block{ width:100%;margin-top:2px; }
.swing-header-row{ display:flex;align-items:center;justify-content:space-between;margin-bottom:12px; }
.res-chip-group{ gap:6px; }
.swing-caption{ text-align:center;font-size:10px;letter-spacing:0.1em;color:var(--text-faint);margin-top:12px; }

/* swing visual: fixed-width slots, only the swung dot moves — grid never reflows */
.swing-visual{ display:flex;justify-content:center;gap:14px;height:30px;margin-top:10px; }
.sv-pair{ position:relative;width:44px;height:20px; }
.sv-dot{ position:absolute;top:7px;width:6px;height:6px;border-radius:50%;background:var(--text-faint); }
.sv-dot.on-beat{ left:2px; }
.sv-dot.off-beat{ background:var(--accent-blue);transition:left .25s ease; }

/* ---- tuner ---- */
.tuner-permission{ flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:22px;text-align:center; }
.tuner-hint{ color:var(--text-muted);font-size:14px;max-width:260px;line-height:1.7; }
.permission-btn{
  background:transparent;border:1px solid var(--hairline);color:var(--text-primary);
  padding:16px 30px;font-size:12px;letter-spacing:0.14em;cursor:pointer;transition:border-color .25s, color .25s;
}
.permission-btn:hover{ border-color:var(--accent-blue);color:var(--accent-blue); }
.tuner-main{ display:flex;flex-direction:column;align-items:center;gap:18px;width:100%;flex:1; }
.note-display{ display:flex;align-items:baseline;gap:6px; }
.note-name{ font-family:'Fraunces',serif;font-weight:500;font-size:82px;line-height:1;color:var(--text-primary);transition:color .2s; }
.note-name.in-tune{ color:var(--good); }
.note-octave{ font-size:20px;color:var(--text-faint); }
.cents-gauge{ width:100%;max-width:320px; }
.gauge-track{ position:relative;height:6px;background:var(--hairline);border-radius:3px;margin-bottom:10px;overflow:visible; }
.gauge-center-line{ position:absolute;left:50%;top:-6px;width:1px;height:18px;background:var(--text-faint);transform:translateX(-50%); }
.gauge-needle{
  position:absolute;top:-7px;width:20px;height:20px;border-radius:50%;background:var(--accent-blue);
  left:50%;transform:translateX(-50%);transition:left .1s linear, background .2s;box-shadow:0 0 10px rgba(46,142,255,0.5);
}
.gauge-needle.in-tune{ background:var(--good); box-shadow:0 0 10px rgba(76,217,138,0.6); }
.gauge-labels{ display:flex;justify-content:space-between;align-items:center;font-size:11px;color:var(--text-faint);letter-spacing:0.08em; }
.gauge-status{ font-size:11px;letter-spacing:0.16em;color:var(--text-muted); }
.gauge-status.in-tune{ color:var(--good); }
.freq-display{ font-family:'Jost',sans-serif;font-size:13px;color:var(--text-faint);letter-spacing:0.04em; }
.string-refs{ margin-top:auto; }
.string-refs .chip{ font-family:'Fraunces',serif;font-style:italic;font-size:14px; }

/* ---- rhythm game ---- */
.game-screen{ padding-top:18px; }
.game-caption{ font-size:11.5px;color:var(--text-faint);text-align:center;max-width:300px;line-height:1.6; }
.game-canvas-wrap{ position:relative;width:100%;max-width:420px; }
#gameCanvas{
  width:100%;aspect-ratio:16/9;
  background:var(--bg-surface);border:1px solid var(--hairline);
  touch-action:none;display:block;
}
.game-countdown{
  position:absolute;inset:0;
  display:none;align-items:center;justify-content:center;
  background:rgba(11,11,10,0.55);
  pointer-events:none;
}
.game-countdown.show{ display:flex; }
.game-countdown span{
  font-family:'Fraunces',serif;font-weight:500;font-size:64px;color:var(--accent-blue);
  text-shadow:0 0 24px rgba(46,142,255,0.6);
  animation:countPop .32s ease-out;
}
@keyframes countPop{
  0%{ transform:scale(0.5); opacity:0; }
  60%{ transform:scale(1.15); opacity:1; }
  100%{ transform:scale(1); opacity:1; }
}
.game-hud{ display:flex;gap:20px;align-items:baseline; }
.game-score{ font-family:'Fraunces',serif;font-weight:500;font-size:34px;color:var(--text-primary); }
.game-best{ font-size:11px;letter-spacing:0.1em;color:var(--text-faint);transition:color .2s; }
@keyframes bestFlash{
  0%{ color:var(--text-faint); text-shadow:0 0 0 rgba(76,217,138,0); }
  40%{ color:var(--good); text-shadow:0 0 10px rgba(76,217,138,0.7); }
  100%{ color:var(--text-faint); text-shadow:0 0 0 rgba(76,217,138,0); }
}
.game-best.new-record{ animation:bestFlash 0.9s ease-out; }
.game-combo{
  font-family:'Jost',sans-serif;font-size:11px;letter-spacing:0.1em;color:var(--accent-blue);
  opacity:0;transition:opacity .2s;
}
.game-combo.show{ opacity:1; animation:comboPop .28s ease-out; }
@keyframes comboPop{
  0%{ transform:scale(0.7); }
  60%{ transform:scale(1.2); }
  100%{ transform:scale(1); }
}
.game-tempo-row{ display:flex;flex-direction:column;align-items:center;gap:8px; }
.game-start-btn{
  margin-top:auto;background:var(--accent-blue);border:none;color:#04070C;
  padding:15px 34px;font-size:11px;letter-spacing:0.16em;font-weight:500;cursor:pointer;
}

/* ---- floating install button ---- */
.fab-install{
  position:fixed;right:calc(20px + env(safe-area-inset-right));bottom:calc(20px + env(safe-area-inset-bottom));
  width:52px;height:52px;border-radius:50%;background:var(--accent-blue);border:none;color:#04070C;
  display:flex;align-items:center;justify-content:center;cursor:pointer;z-index:200;
  box-shadow:0 8px 24px rgba(46,142,255,0.4);transition:transform .15s;
}
.fab-install:active{ transform:scale(0.92); }
.fab-install svg{ width:22px;height:22px; }
.fab-install.hidden{ display:none; }
@media (min-width:640px){
  /* on wide screens the app column is centered with void on either side —
     keep the button anchored to that column, not the browser's edge */
  .fab-install{
    right:max(20px, calc(50vw - 240px + 20px));
  }
}
@media (min-width:900px){
  .fab-install{ right:max(20px, calc(50vw - 260px + 20px)); }
}

/* ---- install guide modal ---- */
.modal-overlay{
  position:fixed;inset:0;z-index:500;background:rgba(6,6,6,0.92);
  display:none;align-items:center;justify-content:center;padding:24px;
}
.modal-overlay.open{ display:flex; }
.modal-card{
  position:relative;background:var(--bg-surface);border:1px solid var(--hairline);
  max-width:380px;width:100%;max-height:84vh;overflow-y:auto;padding:36px 26px 28px;
}
.modal-close{ position:absolute;top:16px;right:16px;background:none;border:none;color:var(--text-faint);font-size:14px;cursor:pointer;padding:6px; }
.modal-close:hover{ color:var(--accent-blue); }
.modal-eyebrow{ font-size:10px;letter-spacing:0.2em;color:var(--accent-blue);margin-bottom:10px; }
.modal-title{ font-family:'Fraunces',serif;font-weight:500;font-size:22px;margin-bottom:12px; }
.modal-desc{ font-size:13px;color:var(--text-muted);line-height:1.8;margin-bottom:22px; }
.guide-block{ margin-bottom:20px; }
.guide-block h3{ font-size:12px;letter-spacing:0.06em;color:var(--text-primary);margin-bottom:10px; }
.guide-block ol{ padding-left:18px;display:flex;flex-direction:column;gap:8px; }
.guide-block li{ font-size:13px;color:var(--text-muted);line-height:1.7; }
.guide-block strong{ color:var(--text-primary);font-weight:500; }
.modal-note{ font-size:11px;color:var(--text-faint);text-align:center;margin-top:6px;margin-bottom:20px; }
.modal-confirm{
  display:block;width:100%;background:var(--accent-blue);border:none;color:#04070C;
  padding:14px 0;font-size:12px;letter-spacing:0.12em;font-weight:500;cursor:pointer;
}

@media (max-width:360px){
  .bpm-input{ font-size:52px; }
  .note-name{ font-size:66px; }
  .seq-track{ grid-template-columns:34px repeat(16, minmax(13px,1fr)); }
  .brand-text span{ font-size:9.5px; }
}

/* ---- tablet / desktop: the control panel stays phone-proportioned on
   purpose (tap targets, sequencer grid), but the surrounding space gets a
   deliberate frame instead of sitting as flat empty void ---- */
@media (min-width:640px){
  body{
    background:
      radial-gradient(ellipse 900px 600px at 50% -10%, rgba(46,142,255,0.07), transparent 65%),
      var(--bg-void);
  }
  .topnav, .app{
    border-left:1px solid var(--hairline);
    border-right:1px solid var(--hairline);
    box-shadow:0 0 60px rgba(0,0,0,0.5);
  }
}
@media (min-width:900px){
  .topnav, .app{ max-width:520px; }
}