:root{
  --bg:#f5f4f0; --surface:#fbfbf9; --panel:#ffffff; --panel-soft:#f7f6f2;
  --ink:#1c1c1a; --ink-hover:#3a3935; --ink-2:#55534d; --sub:#7a776f; --muted:#8a877f;
  --line:#e3e1db; --line-2:#dcdad3; --line-3:#efeee9; --hover:#efeee9; --soft:#f3f2ee; --track:#ebe9e3;
  --accent:#5b3fd6; /* 바이올렛 */
  --accent-2:#7a62e6; --accent-soft:#ece8fd;
  --again:#d9442f; --hard:#d98a00; --good:#2d8f57; --easy:#2f6fd6;
  --font:"IBM Plex Sans KR",sans-serif; --mono:"JetBrains Mono",monospace; --serif:"Gowun Batang","IBM Plex Sans KR",serif;
}
*{box-sizing:border-box}
[hidden]{display:none !important}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font);-webkit-font-smoothing:antialiased;word-break:keep-all}
button,input,textarea{font:inherit;color:inherit}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.mono-label{font-family:var(--mono);font-size:11px;letter-spacing:.12em;color:var(--muted)}
.mono{font-family:var(--mono)}
.app{min-height:100vh;display:flex;flex-direction:column}
.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 28px;border-bottom:1px solid var(--line);background:var(--surface);flex-wrap:wrap}
.brand{display:flex;align-items:baseline;gap:14px;min-width:0;flex-wrap:wrap}
.brand-title{font-size:17px;font-weight:700;letter-spacing:-.01em}
.actions{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.saved{font-size:11.5px;color:var(--muted);font-family:var(--mono)}
.btn{height:36px;padding:0 14px;background:#fff;border:1px solid var(--line-2);border-radius:999px;font-size:13px;cursor:pointer;white-space:nowrap}
.btn:hover{background:var(--hover)}
.btn--solid{background:var(--ink);color:#fff;border:none;font-weight:500}
.btn--solid:hover{background:var(--ink-hover)}
.btn--accent{background:var(--accent);color:#fff;border:none;font-weight:700}
.btn--accent:hover{background:var(--accent-2)}
.btn--accent:disabled{background:#c9c3e6;cursor:default}
.btn--lg{height:48px;padding:0 26px;font-size:15px}
.btn--sm{height:30px;padding:0 12px;font-size:12px}
.btn--danger{color:var(--again);border-color:#f2c8c1}
.link-btn{border:none;background:none;color:var(--sub);font-size:12.5px;cursor:pointer;text-decoration:underline;text-underline-offset:3px}
.icon-btn{width:30px;height:30px;border:none;background:transparent;border-radius:8px;cursor:pointer;color:var(--sub);font-size:14px}
.icon-btn:hover{background:var(--hover);color:var(--ink)}
.text-input{padding:10px 12px;background:var(--surface);border:1px solid var(--line-2);border-radius:10px;font-size:14px;color:var(--ink);width:100%;min-width:0;line-height:1.5;resize:vertical}
.text-input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

.wrap{width:100%;max-width:1080px;margin:0 auto;padding:20px 28px 44px;display:flex;flex-direction:column;gap:18px}

/* 덱 */
.decks{display:flex;gap:10px;align-items:stretch;overflow-x:auto;padding:4px 2px 8px;scrollbar-width:thin}
.deck-list{display:flex;gap:10px}
.deck{flex:none;width:168px;min-height:92px;text-align:left;border:1px solid var(--line);background:#fff;border-radius:16px;padding:12px 14px;cursor:pointer;display:flex;flex-direction:column;gap:6px;position:relative;
  box-shadow:3px 3px 0 -1px #fff,3px 3px 0 0 var(--line),6px 6px 0 -1px #fff,6px 6px 0 0 var(--line);transition:transform .15s;margin-right:6px}
.deck:hover{transform:translateY(-2px)}
.deck[aria-pressed="true"]{border-color:var(--accent);box-shadow:3px 3px 0 -1px #fff,3px 3px 0 0 var(--accent),6px 6px 0 -1px #fff,6px 6px 0 0 #c9bff5;background:var(--accent-soft)}
.deck-name{font-weight:700;font-size:14px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.deck-meta{font-size:11.5px;color:var(--sub)}
.deck-due{margin-top:auto;font-family:var(--mono);font-size:12px;color:var(--accent);font-weight:700}
.deck-due.zero{color:var(--muted);font-weight:400}
.deck-add{flex:none;width:120px;border:1.5px dashed #c9c6bd;background:transparent;border-radius:16px;color:var(--sub);cursor:pointer;font-size:13px}
.deck-add:hover{color:var(--ink);background:rgba(255,255,255,.6)}

.deck-head{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.deck-title-wrap{display:flex;align-items:center;gap:2px;min-width:0}
.deck-title{margin:0 8px 0 0;font-size:24px;letter-spacing:-.02em;overflow-wrap:anywhere}
.tabs{display:flex;background:var(--soft);border-radius:999px;padding:4px}
.tabs button{height:34px;padding:0 16px;border:none;border-radius:999px;background:transparent;font-size:13px;cursor:pointer;color:var(--ink-2)}
.tabs button[aria-selected="true"]{background:#fff;color:var(--ink);font-weight:700;box-shadow:0 1px 3px rgba(0,0,0,.1)}

.view{display:flex;flex-direction:column;gap:16px}
.panel{background:#fff;border:1px solid var(--line);border-radius:20px;padding:18px}
.panel h3{margin:0 0 12px;font-size:15px}

/* 오늘 */
.today{display:flex;justify-content:space-between;align-items:flex-end;gap:20px;flex-wrap:wrap;background:var(--ink);color:#fff;border-radius:24px;padding:24px 28px;
  background-image:radial-gradient(circle at 92% -20%,rgba(122,98,230,.55),transparent 55%),radial-gradient(circle at 0 120%,rgba(91,63,214,.35),transparent 50%)}
.today .mono-label{color:#a9a3c9}
.today-num{margin:6px 0 4px;display:flex;align-items:baseline;gap:10px;flex-wrap:wrap}
.today-num b{font-size:64px;line-height:1;letter-spacing:-.04em}
.today-num span{font-size:16px;color:#d7d3ea}
.today-break{margin:0;font-size:13px;color:#b9b4d4}
.today-side{display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.mini-field{display:flex;flex-direction:column;gap:4px;font-size:11.5px;color:#b9b4d4}
.mini-field input{width:84px;height:40px;border-radius:10px;border:1px solid rgba(255,255,255,.25);background:rgba(255,255,255,.08);color:#fff;padding:0 10px;font-family:var(--mono)}
.today .btn--accent{background:#fff;color:var(--accent)}
.today .btn--accent:hover{background:var(--accent-soft)}
.today .btn--accent:disabled{background:rgba(255,255,255,.3);color:rgba(255,255,255,.7)}

/* 학습 */
.session{display:flex;flex-direction:column;gap:14px;align-items:stretch}
.progress{height:6px;background:var(--track);border-radius:999px;overflow:hidden}
.progress span{display:block;height:100%;width:0;background:var(--accent);transition:width .3s}
.prog-text{margin:-6px 0 0;display:flex;justify-content:space-between;font-size:12.5px;color:var(--sub)}
.stage{perspective:1400px}
.flip{display:block;width:100%;max-width:620px;margin:0 auto;height:340px;border:none;background:none;padding:0;cursor:pointer;-webkit-tap-highlight-color:transparent}
.flip-inner{position:relative;display:block;width:100%;height:100%;transform-style:preserve-3d;transition:transform .55s cubic-bezier(.3,1.25,.45,1)}
.flip.is-flipped .flip-inner{transform:rotateY(180deg)}
.face{position:absolute;inset:0;backface-visibility:hidden;-webkit-backface-visibility:hidden;border-radius:24px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:10px;padding:34px 28px;text-align:center;
  background:#fff;border:1px solid var(--line);box-shadow:0 2px 0 var(--line),0 24px 48px -26px rgba(40,20,120,.35);overflow:auto}
.face.front{background-image:linear-gradient(transparent 31px,#eef0fb 32px);background-size:100% 32px;background-position:0 18px}
.face.back{transform:rotateY(180deg);background:#fdfcff;border-color:#d9d2fb}
.face-tag{position:absolute;top:14px;left:18px;font-size:10.5px;letter-spacing:.14em;color:var(--muted)}
.face.back .face-tag{color:var(--accent)}
.face-text{font-family:var(--serif);font-size:34px;font-weight:700;line-height:1.35;white-space:pre-wrap;overflow-wrap:anywhere;max-width:100%}
.face.back .face-text{font-size:28px;color:var(--accent)}
.face-q{font-size:14px;color:var(--sub);white-space:pre-wrap;overflow-wrap:anywhere;max-width:100%}
.face-hint{position:absolute;bottom:14px;font-size:11.5px;color:var(--muted)}
.flip.is-wiggle .flip-inner{animation:enter .35s cubic-bezier(.3,1.4,.5,1)}
@keyframes enter{from{transform:translateX(40px) rotate(3deg);opacity:0}}
.grades{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;max-width:620px;width:100%;margin:0 auto}
.grade{position:relative;display:flex;flex-direction:column;align-items:center;gap:3px;padding:12px 6px 10px;border-radius:16px;border:1.5px solid;background:#fff;cursor:pointer;transition:transform .1s}
.grade:active{transform:scale(.96)}
.grade b{font-size:15px}
.grade span{font-size:11.5px;color:var(--sub)}
.grade kbd{position:absolute;top:6px;right:8px;font-family:var(--mono);font-size:10px;color:var(--muted)}
.g1{border-color:#f0c4bd;color:var(--again)} .g1:hover{background:#fdf0ee}
.g3{border-color:#f0d9a8;color:var(--hard)} .g3:hover{background:#fdf6e8}
.g4{border-color:#bfe2cd;color:var(--good)} .g4:hover{background:#eef8f2}
.g5{border-color:#c3d4f3;color:var(--easy)} .g5:hover{background:#eef3fd}
.session-foot{display:flex;justify-content:center;gap:16px;align-items:center}
.done{text-align:center;background:#fff;border:1px solid var(--line);border-radius:24px;padding:30px 20px}
.done-emoji{font-size:44px;margin:0}
.done h3{margin:8px 0 6px;font-size:22px}
.done p{color:var(--ink-2);margin:0 0 16px;line-height:1.6}
.note{margin:0;font-size:12.5px;color:var(--sub);line-height:1.6}

/* 카드 관리 */
.add-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.4fr);gap:16px;align-items:start}
.add-grid form{display:flex;flex-direction:column;gap:10px}
.add-grid form > .btn{align-self:flex-end}
.field{display:flex;flex-direction:column;gap:6px;min-width:0}
.field-label{font-size:12px;color:var(--sub);line-height:1.5}
.mono-area{font-family:var(--mono);font-size:13px;tab-size:4}
.bulk-foot{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.bulk-info{font-size:12px;color:var(--accent);margin-left:auto}
.chk{display:inline-flex;align-items:center;gap:6px;font-size:12.5px;color:var(--ink-2);cursor:pointer}
.chk input{accent-color:var(--accent);width:16px;height:16px}
.list-head{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.list-head h3{margin:0;font-size:16px;margin-right:auto}
.search input{height:34px;width:200px;max-width:100%;padding:0 12px;border:1px solid var(--line-2);border-radius:999px;background:#fff;font-size:13px}
.table-wrap{background:#fff;border:1px solid var(--line);border-radius:18px;overflow:hidden}
.cards-table{width:100%;border-collapse:collapse;table-layout:fixed;font-size:13.5px}
.cards-table th{font-size:11.5px;font-weight:500;color:var(--sub);text-align:left;padding:10px 14px;background:var(--panel-soft);border-bottom:1px solid var(--line)}
.cards-table th:nth-child(3){width:110px} .cards-table th:nth-child(4){width:64px}
.cards-table td{padding:10px 14px;border-bottom:1px solid var(--line-3);vertical-align:top;overflow-wrap:anywhere;white-space:pre-wrap}
.cards-table tr:last-child td{border-bottom:none}
.cards-table td.when{font-family:var(--mono);font-size:12px;color:var(--sub);white-space:nowrap}
.cards-table td.when.due{color:var(--accent);font-weight:700}
.cards-table .empty{text-align:center;color:var(--muted);padding:28px}
.pill{display:inline-block;font-size:10.5px;font-family:var(--mono);padding:1px 6px;border-radius:999px;background:var(--accent-soft);color:var(--accent)}

/* 통계 */
.stat-tiles{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}
.tile{background:#fff;border:1px solid var(--line);border-radius:18px;padding:14px 16px}
.tile span{font-size:12px;color:var(--sub)}
.tile b{display:block;font-family:var(--mono);font-size:28px;letter-spacing:-.03em;margin-top:4px}
.tile small{font-size:11.5px;color:var(--muted)}
.charts{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:16px}
.bars{display:flex;align-items:flex-end;gap:5px;height:140px;padding-top:16px}
.bar{flex:1;display:flex;flex-direction:column;align-items:center;gap:4px;height:100%;justify-content:flex-end;min-width:0}
.bar .stackcol{width:100%;max-width:28px;display:flex;flex-direction:column-reverse;border-radius:6px 6px 2px 2px;overflow:hidden;background:var(--line-3);min-height:2px;position:relative}
.bar .ok{background:var(--accent)} .bar .miss{background:#f19a8b} .bar .fore{background:#9b8be8}
.bar .n{font-family:var(--mono);font-size:10px;color:var(--sub);height:12px}
.bar .lb{font-family:var(--mono);font-size:9.5px;color:var(--muted);white-space:nowrap}
.legend-line{margin:10px 0 0;font-size:12px;color:var(--sub);display:flex;gap:6px 14px;align-items:center;flex-wrap:wrap}
.lg{display:inline-block;width:10px;height:10px;border-radius:3px;margin-right:4px;vertical-align:-1px}
.lg.ok{background:var(--accent)} .lg.miss{background:#f19a8b}
.stack{display:flex;height:22px;border-radius:999px;overflow:hidden;background:var(--line-3)}
.stack span{display:block;height:100%;transition:width .4s}

/* 다이얼로그 */
.dlg{border:none;border-radius:20px;padding:0;width:min(520px,calc(100vw - 24px));box-shadow:0 30px 70px -20px rgba(0,0,0,.4);color:var(--ink)}
.dlg::backdrop{background:rgba(28,28,26,.42)}
.dlg-inner{padding:18px 20px;display:flex;flex-direction:column;gap:12px}
.dlg-inner h3{margin:0}
.edit-meta{margin:0;font-size:11.5px;color:var(--muted);line-height:1.6}
.dlg-foot{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.dlg-foot .sp{flex:1}

.toast{position:fixed;left:50%;bottom:24px;transform:translate(-50%,20px);background:var(--ink);color:#fff;border-radius:999px;padding:10px 18px;font-size:13px;display:flex;gap:12px;align-items:center;opacity:0;pointer-events:none;transition:opacity .2s,transform .2s;z-index:2000;max-width:calc(100vw - 32px)}
.toast.is-show{opacity:1;transform:translate(-50%,0);pointer-events:auto}
.toast button{border:none;background:transparent;color:#b9acff;font-weight:700;cursor:pointer;padding:0}

@media (max-width:760px){
  .add-grid,.charts{grid-template-columns:minmax(0,1fr)}
  .stat-tiles{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:640px){
  .topbar{padding:14px 16px}
  .wrap{padding:14px 16px 32px}
  .decks{margin:0 -16px;padding:4px 16px 8px}
  .deck{width:140px}
  .deck-title{font-size:20px}
  .tabs{width:100%}
  .tabs button{flex:1;padding:0 8px}
  .today{padding:20px}
  .today-num b{font-size:52px}
  .today-side{width:100%;justify-content:space-between}
  .flip{height:300px}
  .face-text{font-size:28px}
  .face.back .face-text{font-size:23px}
  .grades{gap:6px}
  .grade{padding:10px 2px 8px;border-radius:12px}
  .grade b{font-size:14px}
  .grade kbd{display:none}
  .cards-table th:nth-child(3){width:78px}
  .cards-table th:nth-child(4){width:44px}
  .cards-table td,.cards-table th{padding:9px 8px}
  .search{flex:1}
  .search input{width:100%}
}
@media (prefers-reduced-motion:reduce){*{animation:none !important;transition:none !important}}

/* 다크 모드 (인쇄는 라이트 그대로) */
@media screen{
  :root[data-theme="dark"]{
    color-scheme:dark;
    --bg:#141318; --surface:#1a1920; --panel:#1f1e26; --panel-soft:#24232c;
    --ink:#ecebf0; --ink-hover:#ffffff; --ink-2:#c9c7d1; --sub:#a09eab; --muted:#8a8895;
    --line:#2e2d36; --line-2:#393843; --line-3:#26252d; --hover:#2a2932; --soft:#26252d; --track:#34333d;
    --accent:#a593ff; --accent-2:#b9aaff; --accent-soft:rgba(165,147,255,.16);
    --again:#ff7d6b; --hard:#f0b13c; --good:#52c78a; --easy:#72a2ff;
    --fc-new:#4a4470; --fc-learn:#7f6fd6;
  }
  :root[data-theme="dark"] .btn{background:var(--panel)}
  :root[data-theme="dark"] .btn:hover{background:var(--hover)}
  :root[data-theme="dark"] .btn--solid{background:var(--ink);color:var(--bg)}
  :root[data-theme="dark"] .btn--solid:hover{background:var(--ink-hover)}
  :root[data-theme="dark"] .btn--accent{background:var(--accent);color:var(--bg)}
  :root[data-theme="dark"] .btn--accent:hover{background:var(--accent-2)}
  :root[data-theme="dark"] .btn--accent:disabled{background:#3a3552;color:var(--muted)}
  :root[data-theme="dark"] .btn--danger{border-color:rgba(255,125,107,.4)}
  :root[data-theme="dark"] .deck{background:var(--panel);box-shadow:3px 3px 0 -1px var(--bg),3px 3px 0 0 var(--line-2),6px 6px 0 -1px var(--bg),6px 6px 0 0 var(--line-2)}
  :root[data-theme="dark"] .deck[aria-pressed="true"]{background:#2a263d;box-shadow:3px 3px 0 -1px var(--bg),3px 3px 0 0 var(--accent),6px 6px 0 -1px var(--bg),6px 6px 0 0 #574a96}
  :root[data-theme="dark"] .deck-add{border-color:var(--line-2)}
  :root[data-theme="dark"] .deck-add:hover{background:var(--hover)}
  :root[data-theme="dark"] .tabs button[aria-selected="true"]{background:var(--track);box-shadow:0 1px 3px rgba(0,0,0,.35)}
  :root[data-theme="dark"] .panel,:root[data-theme="dark"] .done,:root[data-theme="dark"] .table-wrap,:root[data-theme="dark"] .tile,:root[data-theme="dark"] .search input{background:var(--panel)}
  :root[data-theme="dark"] .today{background-color:#1d1a2e;border:1px solid #2f2a48}
  :root[data-theme="dark"] .today .btn--accent{background:var(--accent);color:var(--bg)}
  :root[data-theme="dark"] .today .btn--accent:hover{background:var(--accent-2)}
  :root[data-theme="dark"] .today .btn--accent:disabled{background:rgba(255,255,255,.12);color:rgba(255,255,255,.55)}
  :root[data-theme="dark"] .face{background:var(--panel);border-color:var(--line-2);box-shadow:0 2px 0 var(--line-2),0 24px 48px -26px rgba(0,0,0,.7)}
  :root[data-theme="dark"] .face.front{background-image:linear-gradient(transparent 31px,#2a2838 32px)}
  :root[data-theme="dark"] .face.back{background:#221f2e;border-color:#4a3f80}
  :root[data-theme="dark"] .grade{background:var(--panel)}
  :root[data-theme="dark"] .g1{border-color:rgba(255,125,107,.4)} :root[data-theme="dark"] .g1:hover{background:rgba(255,125,107,.1)}
  :root[data-theme="dark"] .g3{border-color:rgba(240,177,60,.4)} :root[data-theme="dark"] .g3:hover{background:rgba(240,177,60,.1)}
  :root[data-theme="dark"] .g4{border-color:rgba(82,199,138,.4)} :root[data-theme="dark"] .g4:hover{background:rgba(82,199,138,.1)}
  :root[data-theme="dark"] .g5{border-color:rgba(114,162,255,.4)} :root[data-theme="dark"] .g5:hover{background:rgba(114,162,255,.1)}
  :root[data-theme="dark"] .dlg{background:var(--panel);border:1px solid var(--line-2);box-shadow:0 30px 70px -20px rgba(0,0,0,.7)}
  :root[data-theme="dark"] .dlg::backdrop{background:rgba(0,0,0,.6)}
  :root[data-theme="dark"] .toast{color:var(--bg)}
  :root[data-theme="dark"] .toast button{color:#5b3fd6}
}