:root{
  --bg:#0b1020; --bg2:#121a30; --card:#161f38; --card2:#1c2745;
  --line:#26314f; --txt:#e8ecf6; --mut:#93a0bd;
  --pri:#4f7cff; --pri2:#22d3ee; --ok:#2ecc9b; --bad:#ff5d73; --warn:#ffb020;
  --r:14px;
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0}
body{
  background:radial-gradient(1200px 600px at 50% -10%,#182746 0%,transparent 60%),var(--bg);
  background-color:var(--bg);
  color:var(--txt);
  font-family:-apple-system,"Segoe UI","PingFang TC","Microsoft JhengHei",system-ui,sans-serif;
  font-size:16px;line-height:1.55;-webkit-text-size-adjust:100%;
}
a{color:inherit;text-decoration:none}
.wrap{max-width:760px;margin:0 auto;padding:16px 16px 64px}

/* topbar */
.topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;
  padding:12px 16px;background:rgba(11,16,32,.85);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.brand{font-weight:800;font-size:20px;letter-spacing:.5px;background:linear-gradient(90deg,var(--pri),var(--pri2));
  -webkit-background-clip:text;background-clip:text;color:transparent}
.brand span{margin-left:4px;font-weight:600;color:var(--mut);-webkit-text-fill-color:var(--mut)}
.topnav{display:flex;gap:6px}
.topnav a{padding:7px 12px;border-radius:10px;font-size:14px;color:var(--mut)}
.topnav a:active{background:var(--card)}

/* 使用者列（登入後才出現） */
.userbar{max-width:760px;margin:0 auto;padding:8px 16px 0;display:flex;align-items:center;
  gap:10px;font-size:13px;color:var(--mut)}
.userbar .uname{font-weight:700;color:var(--txt)}
.userbar a{color:var(--mut);padding:4px 8px;border-radius:8px;border:1px solid var(--line)}
.userbar form{margin:0 0 0 auto}
.userbar button{background:transparent;color:var(--mut);border:1px solid var(--line);
  border-radius:8px;padding:4px 10px;font-size:13px;cursor:pointer;font-family:inherit}
.userbar a:active,.userbar button:active{background:var(--card)}

/* 登入 / 註冊 / 改密碼 */
.auth-hero{text-align:center;margin-top:18px}
.auth-panel{max-width:420px;margin:12px auto 0}
.auth-alt{text-align:center;color:var(--mut);font-size:14px;margin-top:14px}
.auth-alt a{color:var(--pri2);font-weight:600}
.err{color:var(--bad);font-size:14px;margin:-4px 0 12px}
.ok-msg{color:var(--ok);font-size:14px;margin:0 0 12px}

/* hero */
.hero h1{font-size:24px;margin:8px 0 2px}
.hero .sub{color:var(--mut);margin:0 0 14px;font-size:14px}
.countdowns{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.cd-card{background:linear-gradient(160deg,var(--card2),var(--card));border:1px solid var(--line);
  border-radius:var(--r);padding:16px;text-align:center}
.cd-days{font-size:40px;font-weight:800;line-height:1;color:var(--pri2)}
.cd-days.soon{color:var(--warn)} .cd-days.past{color:var(--mut);font-size:26px}
.cd-days span{font-size:14px;font-weight:600;color:var(--mut);margin-left:4px}
.cd-name{margin-top:8px;font-size:14px;font-weight:600}
.cd-date{color:var(--mut);font-size:12px}

.block{margin-top:26px}
.block h2{font-size:18px;margin:0 0 12px}
.sub{color:var(--mut);font-size:13px;margin:-6px 0 12px}

/* subject cards */
.subject-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.subj-card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:14px}
.subj-card.weak{border-color:var(--warn);box-shadow:0 0 0 1px var(--warn) inset,0 8px 24px -12px var(--warn)}
.subj-head{display:flex;align-items:center;justify-content:space-between;gap:6px;min-height:20px}
.subj-level{font-size:12px;color:var(--mut);font-weight:700}
.weak-tag{font-size:10px;font-weight:800;color:#0b1020;background:var(--warn);padding:2px 6px;border-radius:20px}
.subj-label{font-size:14px;font-weight:600;margin:6px 0 10px;min-height:38px}
.subj-stat{display:flex;justify-content:space-between;text-align:center;margin-bottom:12px}
.subj-stat b{display:block;font-size:17px} .subj-stat small{color:var(--mut);font-size:11px}
.subj-actions{display:flex;gap:8px}

/* entries */
.entry-grid{display:grid;grid-template-columns:1fr;gap:10px}
.entry{display:flex;flex-direction:column;background:var(--card);border:1px solid var(--line);
  border-radius:var(--r);padding:14px 16px}
.entry:active{background:var(--card2)}
.entry-t{font-weight:700;font-size:15px}
.entry-t em{font-style:normal;color:var(--pri2);margin-left:6px}
.entry-d{color:var(--mut);font-size:13px}

/* panels & forms */
.panel{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px;margin-top:12px}
.hidden{display:none !important}
.field{display:flex;flex-direction:column;gap:6px;margin-bottom:14px;font-size:14px;color:var(--mut)}
.field.check{flex-direction:row;align-items:center;gap:8px;color:var(--txt)}
select,input[type=number],input[type=text],input[type=password]{width:100%;background:var(--bg2);
  color:var(--txt);border:1px solid var(--line);
  border-radius:10px;padding:11px 12px;font-size:15px;appearance:none}
input[type=text]:focus,input[type=password]:focus{outline:none;border-color:var(--pri)}
input[type=checkbox]{width:20px;height:20px;accent-color:var(--pri)}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;width:100%;
  background:linear-gradient(90deg,var(--pri),var(--pri2));color:#06122b;font-weight:800;
  border:none;border-radius:12px;padding:13px 16px;font-size:15px;cursor:pointer}
.btn:active{filter:brightness(.92)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.ghost{background:transparent;color:var(--txt);border:1px solid var(--line)}
.btn.sm{width:auto;flex:1;padding:9px 10px;font-size:13px;border-radius:10px}

/* question */
.qmeta{color:var(--mut);font-size:13px;margin-bottom:8px}
.stem{font-size:17px;font-weight:600;line-height:1.6;margin-bottom:14px;white-space:pre-wrap;word-break:break-word}
.options{display:flex;flex-direction:column;gap:10px}
.opt{display:flex;gap:10px;align-items:flex-start;background:var(--bg2);border:1px solid var(--line);
  border-radius:12px;padding:12px 14px;cursor:pointer;transition:border-color .15s,background .15s}
.opt:active{background:var(--card2)}
.opt .k{font-weight:800;color:var(--pri2);min-width:18px}
.opt.chosen{border-color:var(--pri)}
.opt.correct{border-color:var(--ok);background:rgba(46,204,155,.12)}
.opt.wrong{border-color:var(--bad);background:rgba(255,93,115,.12)}
.opt.disabled{cursor:default;pointer-events:none}
.qbar{display:flex;gap:10px;margin-top:16px}
.feedback{margin-top:14px;border-radius:12px;padding:12px 14px;font-size:14px;border:1px solid var(--line)}
.feedback.ok{border-color:var(--ok);background:rgba(46,204,155,.1)}
.feedback.bad{border-color:var(--bad);background:rgba(255,93,115,.1)}
.feedback .verdict{font-weight:800;margin-bottom:6px}
.feedback .expl{color:var(--txt);white-space:pre-wrap}
.feedback .expl.mut{color:var(--mut);font-style:italic}
.toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);background:var(--bad);
  color:#fff;padding:10px 16px;border-radius:20px;font-size:14px;z-index:50}

/* exam nav grid */
.qnav{display:grid;grid-template-columns:repeat(auto-fill,minmax(38px,1fr));gap:8px;margin-top:16px}
.qnav button{background:var(--bg2);border:1px solid var(--line);color:var(--mut);border-radius:9px;
  padding:8px 0;font-size:13px;cursor:pointer}
.qnav button.answered{border-color:var(--pri);color:var(--txt)}
.qnav button.current{background:var(--pri);color:#06122b;font-weight:800}

/* exam result */
.score-big{font-size:56px;font-weight:900;text-align:center;line-height:1}
.score-big.pass{color:var(--ok)} .score-big.fail{color:var(--bad)}
.score-sub{text-align:center;color:var(--mut);margin-bottom:16px}
.review-item{border-top:1px solid var(--line);padding:14px 0}
.review-item .rq{font-weight:600;margin-bottom:8px;white-space:pre-wrap}
.review-item .ro{font-size:14px;padding:6px 10px;border-radius:8px;margin:4px 0}
.review-item .ro.a{background:rgba(46,204,155,.12);color:var(--ok)}
.review-item .ro.x{background:rgba(255,93,115,.12);color:var(--bad)}
.review-item .rskip{display:inline-block;background:rgba(255,255,255,.10);color:var(--mut);font-size:12px;font-weight:600;padding:1px 8px;border-radius:20px;margin-right:6px;vertical-align:middle}
.review-item .rexpl{color:var(--mut);font-size:13px;margin-top:6px;white-space:pre-wrap}

/* wrongbook */
.count-badge{background:var(--bad);color:#fff;font-size:13px;padding:2px 10px;border-radius:20px;vertical-align:middle}
.wb-list{display:flex;flex-direction:column;gap:10px}
.wb-item{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:14px}
.wb-stem{font-size:15px;font-weight:600;margin-bottom:8px;white-space:pre-wrap;word-break:break-word}
.wb-meta{color:var(--mut);font-size:12px;margin-bottom:10px}
.wb-actions{display:flex;gap:8px}
@media(min-width:620px){.entry-grid{grid-template-columns:1fr 1fr 1fr}}

/* 題目附圖 */
.qimg-slot:empty{display:none}
.qimg-slot{margin:10px 0}
.qimg{max-width:100%;height:auto;border:1px solid var(--line);border-radius:10px;background:#fff;padding:6px;cursor:zoom-in;display:block}
.review-item .qimg{margin:8px 0}
.imgzoom{position:fixed;inset:0;background:rgba(0,0,0,.85);display:none;align-items:center;justify-content:center;z-index:1000;padding:16px;cursor:zoom-out}
.imgzoom.show{display:flex}
.imgzoom img{max-width:100%;max-height:100%;background:#fff;border-radius:8px}

/* 背景音樂 pill */
#bgm-holder{position:fixed;left:-9999px;top:-9999px;width:200px;height:113px;opacity:0;pointer-events:none}
#bgm-pill{position:fixed;left:12px;bottom:12px;z-index:40;display:flex;align-items:center;gap:8px;
  padding:6px 10px;border-radius:22px;background:rgba(18,26,48,.9);border:1px solid var(--line);
  backdrop-filter:blur(8px);box-shadow:0 8px 24px -12px rgba(0,0,0,.6);font-size:12px}
#bgm-pill .eq{display:inline-flex;align-items:flex-end;gap:2px;height:14px}
#bgm-pill .eq i{width:3px;height:5px;background:var(--pri2);border-radius:2px}
#bgm-pill.playing:not(.muted):not(.off) .eq i{animation:bgmeq .9s ease-in-out infinite}
#bgm-pill.playing:not(.muted):not(.off) .eq i:nth-child(2){animation-delay:.15s}
#bgm-pill.playing:not(.muted):not(.off) .eq i:nth-child(3){animation-delay:.3s}
#bgm-pill.muted .eq i,#bgm-pill.off .eq i{background:var(--mut)}
@keyframes bgmeq{0%,100%{height:4px}50%{height:13px}}
#bgm-pill button{background:transparent;border:none;color:var(--txt);font-size:12px;font-weight:700;
  padding:3px 6px;border-radius:8px;cursor:pointer;line-height:1;white-space:nowrap}
#bgm-pill button:active{background:var(--card2)}
#bgm-pill.off #bgm-play,#bgm-pill.muted #bgm-mute{color:var(--pri2)}
@media(max-width:520px){
  #bgm-pill{left:8px;bottom:8px;gap:5px;padding:5px 8px;font-size:11px}
  #bgm-pill button{padding:2px 4px;font-size:11px}
}