/* Tiếng Trung Cô Nga Bùi · HSK2 3.0 — giao diện chung (theo mẫu bộ New HSK1 "giao diện mới") */
:root{
  --teal:#0d7377; --teal-2:#14a085; --teal-bg:#e8f8f5; --teal-line:#a8d8d8;
  --red:#c0392b; --red-2:#e74c3c; --orange:#c2410c; --orange-2:#f97316; --orange-bg:#fff4ec;
  --ink:#1a1a2e; --muted:#5f6b78; --line:#e2dcd2; --bg:#f7f3ed; --card:#fff;
  --ok:#166534; --ok-bg:#ecfdf3; --bad:#b42318; --bad-bg:#fef3f2;
  --zh:"Helvetica Neue",Arial,"Segoe UI",Roboto,"PingFang SC","Hiragino Sans GB","Noto Sans SC","Noto Sans CJK SC","Microsoft YaHei","Source Han Sans SC",sans-serif;
  --radius:16px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--ink);background:var(--bg)}
a{color:var(--teal)}
button{font:inherit;cursor:pointer}
:focus-visible{outline:3px solid var(--orange-2);outline-offset:2px;border-radius:8px}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}
.skip{position:absolute;left:-999px}.skip:focus{left:8px;top:8px;background:#fff;padding:8px 12px;z-index:9}

/* ---------- Đầu trang thương hiệu ---------- */
.backdrop{background:linear-gradient(135deg,#0a4f52 0%,#0d7377 40%,#14a085 70%,#c0392b 100%);padding:14px 20px}
.backdrop-inner{display:flex;align-items:center;gap:14px;max-width:1040px;margin:0 auto}
.backdrop-logo{width:68px;height:68px;border-radius:50%;object-fit:contain;background:#fff;padding:4px;border:3px solid rgba(255,255,255,.35);box-shadow:0 4px 14px rgba(0,0,0,.25);display:block}
.backdrop-text{color:#fff;min-width:0}
.bt-name{font-size:clamp(16px,3vw,22px);font-weight:700;line-height:1.2;text-shadow:0 1px 4px rgba(0,0,0,.25)}
.bt-sub{font-size:clamp(11.5px,1.8vw,13.5px);opacity:.9;margin:2px 0 6px}
.bt-links{display:flex;flex-wrap:wrap;gap:6px}
.bt-phone,.bt-link{display:inline-block;border-radius:999px;padding:3px 12px;font-size:14px;font-weight:700;text-decoration:none}
.bt-phone{background:#fff;color:var(--teal)}
.bt-link{color:#fff;background:rgba(255,255,255,.15);border:1px solid rgba(255,255,255,.35)}
.subbar{position:sticky;top:0;z-index:6;display:flex;align-items:center;justify-content:space-between;gap:10px;padding:8px 16px;background:#fff;border-bottom:1px solid var(--line)}
.sb-title{font-weight:700;text-decoration:none;color:var(--ink);font-size:15px}
.present-btn{border:1.5px solid var(--teal);background:#fff;color:var(--teal);border-radius:999px;padding:5px 14px;font-size:14px;font-weight:700}
.present-btn:hover{background:var(--teal);color:#fff}
/* Trình chiếu */
.present-ctrl{display:none}
body.present .backdrop,body.present .foot,body.present .subbar{display:none}
body.present{background:#fbf8f3}
body.present main{max-width:none;padding:18px 3vw 90px;zoom:var(--pz,1.3)}
body.present .present-ctrl{display:flex;gap:6px;position:fixed;right:14px;bottom:14px;z-index:30;background:rgba(26,26,46,.88);padding:6px;border-radius:14px}
body.present .present-ctrl button{border:0;background:#fff;color:var(--ink);border-radius:10px;padding:8px 12px;font-weight:800;font-size:15px}
body.present .wb{height:calc(100vh - 140px)}

main{max-width:1040px;margin:0 auto;padding:14px 16px 40px;outline:none}
main:focus,main:focus-visible{outline:none}
.loading{color:var(--muted)}
.foot{max-width:1040px;margin:0 auto;padding:16px;border-top:1px solid var(--line);font-size:14px}
.foot p{margin:4px 0}
.muted{color:var(--muted)}
body.hide-py .py{display:none!important}
body.hide-vi .vi{display:none!important}

/* ---------- Thanh chọn bài ---------- */
.ltabs{display:flex;gap:8px;overflow-x:auto;padding:4px 2px 12px;margin:0 -2px 6px;scrollbar-width:thin}
.lt{flex:none;display:flex;align-items:center;gap:8px;padding:5px 14px 5px 5px;border:2px solid var(--line);border-radius:999px;background:#fff;text-decoration:none;color:var(--ink);font-weight:600;white-space:nowrap}
.lt-n{width:30px;height:30px;border-radius:50%;background:var(--teal);color:#fff;display:grid;place-items:center;font-size:13px;font-weight:800}
.lt-zh{font-family:var(--zh);font-size:15px}
.lt[aria-current="page"]{border-color:var(--teal);box-shadow:0 0 0 2px var(--teal-bg)}
.lt.off{opacity:.5}
.lt.off .lt-n{background:#9aa5ad}

/* ---------- Hero ---------- */
.hero{position:relative;overflow:hidden;background:linear-gradient(135deg,#0a4f52 0%,#0d7377 55%,#14a085 100%);color:#fff;border-radius:22px;padding:24px 26px 20px;margin:6px 0 12px;box-shadow:0 8px 24px rgba(13,115,119,.25)}
.hero-title[lang]{font-family:var(--zh)}
.hero-badge{display:inline-block;background:rgba(255,255,255,.15);border:1px solid rgba(255,255,255,.3);border-radius:999px;padding:3px 12px;font-size:12.5px;font-weight:700;letter-spacing:.06em}
.hero-title{font-family:inherit;font-size:clamp(28px,5.5vw,46px);line-height:1.2;margin:10px 0 4px;color:#fff}
.hero-py{margin:0;font-weight:700;font-size:17px}
.hero-vi{margin:0 0 12px;font-style:italic;opacity:.92}
.hero p{position:relative}
.hero-chips{display:flex;flex-wrap:wrap;gap:8px;position:relative}
.hero-chips span{background:rgba(0,0,0,.22);border-radius:999px;padding:5px 13px;font-size:14px;font-weight:600}
.hero-prog{display:flex;align-items:center;gap:12px;margin-top:16px;font-size:13.5px;position:relative}
.hero-prog .bar{flex:1}
.hero-bg{position:absolute;right:-6px;top:-30px;font-family:var(--zh);font-size:190px;line-height:1;color:rgba(255,255,255,.08);font-weight:900;pointer-events:none}
.bar{height:8px;background:#ede7dd;border-radius:99px;overflow:hidden}
.bar.light{background:rgba(255,255,255,.22)}
.bar>span{display:block;height:100%;background:var(--teal-2)}
.bar.light>span{background:#fff}
.tracks{display:flex;flex-wrap:wrap;align-items:center;gap:6px;margin:4px 0 12px}
.trk{border:1.5px solid var(--line);background:#fff;border-radius:999px;padding:3px 12px;font-size:13.5px;font-weight:700;color:var(--ink)}
.trk:hover{border-color:var(--teal);color:var(--teal)}
.trk.all{background:var(--teal);border-color:var(--teal);color:#fff}
.all-vocab{display:flex;flex-direction:column;gap:8px;background:var(--teal-bg);border-color:var(--teal-line)}
.all-vocab p{margin:0}
.trk.stop{padding:3px 10px}

/* ---------- Lưới ô chức năng ---------- */
.tiles{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:10px 0 18px}
.tile{display:flex;align-items:center;gap:16px;background:#fff;border:1.5px solid var(--line);border-radius:18px;padding:16px 18px;text-decoration:none;color:var(--ink);box-shadow:0 1px 3px rgba(0,0,0,.04);transition:border-color .15s,box-shadow .15s}
.tile:hover{border-color:#cbbfae;box-shadow:0 4px 14px rgba(0,0,0,.07)}
.ti{flex:none;width:58px;height:58px;border-radius:14px;display:grid;place-items:center;color:#fff}
.ico{display:inline-grid;place-items:center}
.tl{flex:1;display:flex;flex-direction:column;min-width:0}
.tl strong{font-size:18px}
.tl small{font-size:13px;color:var(--muted)}
.tile.done .tl small{color:var(--ok);font-weight:600}
.tile>.ico:last-child{color:#9aa5ad}
.btn-result{display:flex;align-items:center;justify-content:center;gap:10px;background:var(--red);color:#fff;text-decoration:none;font-size:18px;font-weight:700;border-radius:18px;padding:16px;box-shadow:0 4px 14px rgba(192,57,43,.3)}
.btn-result:hover{background:#a93226}

/* ---------- Trang mục ---------- */
.back{display:inline-block;margin:2px 0 8px;font-weight:600;text-decoration:none}
.mod-head{display:flex;align-items:center;gap:14px;margin:4px 0 12px}
.mod-head h1{margin:0}
.mod-head p{margin:0}

/* Thanh ẩn/hiện phiên âm – nghĩa */
.pytoggle{display:flex;flex-wrap:wrap;align-items:center;gap:8px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:8px 10px;margin:4px 0 12px}
.pt-btn{border:2px solid var(--teal);background:var(--teal);color:#fff;border-radius:999px;padding:5px 14px;font-weight:700;font-size:14.5px}
.pt-btn[aria-pressed="false"]{background:#fff;color:var(--muted);border-color:#c9c1b4}
.hero .hero-py.py{color:#fff;font-size:17px}
.hero .hero-vi.vi{color:#fff;font-size:16px}

/* ---------- Thẻ, chữ ---------- */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;margin:14px 0}
h1{font-size:24px;line-height:1.3;margin:6px 0}
h2{font-size:20px;margin:22px 0 8px;color:var(--teal)}
h3{font-size:17px;margin:4px 0 8px}
h3.sec{margin-top:22px;color:var(--teal)}
.zh{font-family:var(--zh);font-size:20px;line-height:1.7;letter-spacing:.02em}
.zh.big{font-size:34px;font-weight:700}
.py{color:var(--teal);font-size:15px}
.vi{color:var(--muted);font-size:15px}
.tri>div{margin:1px 0}
.badge{display:inline-block;font-size:12.5px;font-weight:600;padding:2px 9px;border-radius:999px;border:1px solid var(--line);background:#fff;color:var(--muted);margin:0 4px 4px 0}
.badge.skill{background:var(--teal-bg);border-color:var(--teal-line);color:var(--teal)}
.badge.own{background:var(--orange-bg);border-color:#fed7b8;color:var(--orange)}
.notice{background:var(--orange-bg);border:1px solid #fed7b8;border-left:5px solid var(--orange-2);border-radius:10px;padding:10px 14px;font-size:14.5px;margin:10px 0}
.notice.info{background:var(--teal-bg);border-color:var(--teal-line);border-left-color:var(--teal)}
.small{font-size:14px}

/* Nút */
.btn{display:inline-flex;align-items:center;gap:6px;border:1.5px solid var(--teal);background:var(--teal);color:#fff;border-radius:10px;padding:9px 16px;font-weight:600;text-decoration:none;min-height:42px}
.btn:hover{background:#0a5d60}
.btn.ghost{background:#fff;color:var(--teal)}
.btn.ghost:hover{background:var(--teal-bg)}
.btn.warm{background:var(--red);border-color:var(--red);color:#fff}
.btn:disabled{opacity:.45;cursor:not-allowed}
.btn.sm{padding:5px 11px;min-height:34px;font-size:14px}
.row{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.row.center{justify-content:center;margin:10px 0}
.spacer{flex:1}
.say{border:1.5px solid var(--teal-line);background:#fff;color:var(--teal);border-radius:999px;width:36px;height:36px;font-size:16px;flex:none;display:inline-grid;place-items:center}
.say:hover{background:var(--teal-bg)}
.tts-tag{font-size:12px;color:var(--muted);border:1px dashed var(--line);border-radius:6px;padding:1px 6px;margin-left:4px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:8px 0 12px}
.chip{border:1.5px solid var(--line);background:#fff;border-radius:999px;padding:5px 14px;font-weight:600;color:var(--ink)}
.chip[lang]{font-family:var(--zh);font-size:18px}
.chip[aria-pressed="true"]{background:var(--teal);border-color:var(--teal);color:#fff}

/* Trang danh sách bài */
.lessons{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));margin-top:16px}
.lcard{display:flex;flex-direction:column;gap:6px;background:#fff;border:1.5px solid var(--line);border-radius:var(--radius);padding:14px 16px;text-decoration:none;color:var(--ink)}
a.lcard:hover{border-color:var(--teal);box-shadow:0 2px 10px rgba(13,115,119,.12)}
.lcard.off{background:#fbf9f5}
.lcard.off .zh{color:#4a5560}
.lnum{font-size:13.5px;font-weight:900;color:var(--red);letter-spacing:.06em}
.lcard .zh{font-size:21px;line-height:1.45;font-weight:700;color:var(--ink)}
.lcard .py{font-weight:600}
.lcard .vi{font-weight:600;color:#3d4852}
.lcard .badge{font-weight:700;color:#5f6b78}
.lcard .small{font-weight:600}

/* Từ vựng */
.grp-head{display:flex;flex-wrap:wrap;align-items:center;gap:10px;background:var(--teal-bg);border:1px solid var(--teal-line);border-radius:12px;padding:8px 12px;margin:16px 0 10px;color:var(--teal)}
.vgroup{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(240px,1fr))}
.vcard{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:14px}
.vword{display:flex;align-items:center;gap:10px}
.vnum{font-size:13px;font-weight:700;color:var(--muted);min-width:1.2em}
.vword .hz{font-family:var(--zh);font-size:38px;line-height:1.2;font-weight:600}
.pos{font-size:13px;color:var(--orange);font-weight:600}
.vex{border-top:1px dashed var(--line);margin-top:8px;padding-top:8px}
.vex .zh{font-size:18px}

/* Bảng từ vựng */
.vt-all{margin:0 0 12px}
.vt-wrap{background:#fff;border:1px solid var(--line);border-radius:var(--radius);overflow-x:auto}
.vt{width:100%;border-collapse:collapse;min-width:680px}
.vt th{font-size:12px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);text-align:left;padding:12px;border-bottom:2px solid var(--line)}
.vt td{padding:10px 12px;border-bottom:1px solid var(--line);vertical-align:middle}
.vt tr:hover td{background:#f6fbfa}
.vt-grp td{background:var(--teal-bg);color:var(--teal);font-weight:700;padding:8px 12px}
.vt-gplay{margin-left:14px;border:1.5px solid var(--teal);background:#fff;color:var(--teal);border-radius:999px;padding:3px 12px;font-weight:700;font-size:13.5px}
.vt-gplay:hover{background:var(--teal);color:#fff}
.vt-num{font-weight:800;color:var(--muted);width:36px}
.vt-cnw{display:flex;align-items:center;gap:8px;white-space:nowrap}
.vt-cn span[lang]{font-family:var(--zh);font-size:28px;font-weight:600}
.vt-py .py{font-size:16px;font-weight:600;white-space:nowrap}
.vt-vn .vi{color:var(--ink);font-size:15px}
.vt-type{display:inline-block;font-size:12.5px;font-weight:700;background:#f3eee6;border-radius:999px;padding:2px 10px;white-space:nowrap}
.vt-ex .zh{font-size:17px;line-height:1.5}
.vt-ex .py,.vt-ex .vi{font-size:13.5px}

/* Chữ Hán */
.hz-stage{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:16px}
.hz-boxes{display:flex;flex-direction:column;gap:16px;margin-top:12px}
.hz-cell{display:flex;flex-wrap:wrap;gap:16px;align-items:flex-start;width:100%;border-top:1px dashed var(--line);padding-top:14px}
.hz-cell:first-child{border-top:0;padding-top:0}
.hz-left{display:flex;flex-direction:column;align-items:center;gap:6px;text-align:center;width:190px}
.hz-info{flex:1;min-width:260px}
.hz-title{display:flex;align-items:baseline;gap:12px;margin-bottom:4px}
.hz-big{font-family:var(--zh);font-size:40px;font-weight:700;line-height:1.1}
.hz-hv{font-weight:800;letter-spacing:.08em;color:var(--red)}
.hz-info dl{display:grid;grid-template-columns:auto 1fr;gap:6px 12px;margin:6px 0 0}
.hz-info dt{font-weight:700;color:var(--muted);font-size:14px;padding-top:2px}
.hz-info dd{margin:0}
.hz-rad{font-family:var(--zh);font-size:22px;color:var(--red);font-weight:700}
.hz-parts{display:flex;flex-wrap:wrap;align-items:center;gap:6px}
.hz-part{display:flex;flex-direction:column;align-items:center;border:1.5px solid var(--line);border-radius:10px;padding:4px 10px;background:#fffdfa;min-width:64px;text-align:center}
.hz-part b{font-family:var(--zh);font-size:24px;line-height:1.3}
.hz-part small{font-size:12.5px;color:var(--muted)}
.hz-part.is-rad{border-color:#f0b4ac;background:#fdf0ef}
.hz-part.is-rad b{color:var(--red)}
.hz-part.txt b{font-family:inherit;font-size:15px;line-height:1.6}
.hz-plus{font-weight:800;color:var(--muted)}
.tzg{width:150px;height:150px;border:2px solid #c9a99f;border-radius:6px;background:
  linear-gradient(to right,transparent 49.5%,#ead7d2 49.5%,#ead7d2 50.5%,transparent 50.5%),
  linear-gradient(to bottom,transparent 49.5%,#ead7d2 49.5%,#ead7d2 50.5%,transparent 50.5%),#fffdfa}

/* Flashcard */
.fc{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;width:100%;max-width:440px;min-height:260px;margin:10px auto;border:2px solid var(--line);border-radius:22px;background:#fff;box-shadow:0 6px 18px rgba(0,0,0,.07);padding:20px;color:var(--ink)}
.fc.back{background:var(--teal-bg);border-color:var(--teal-line)}
.fc-hz{font-family:var(--zh);font-size:72px;font-weight:700;line-height:1.1}
.fc-py{font-size:28px;color:var(--teal);font-weight:700}
.fc-vi{font-size:20px;font-weight:600}
.fc-ex{font-family:var(--zh);font-size:19px}

/* Game */
.gboard{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:10px 0}
.gcol{display:flex;flex-direction:column;gap:8px}
.gbtn{border:1.5px solid var(--line);background:#fff;border-radius:12px;padding:10px 12px;min-height:52px;text-align:center;font-weight:600;color:var(--ink)}
.gbtn.zhb{font-family:var(--zh);font-size:22px}
.gbtn[aria-pressed="true"]{border-color:var(--teal);background:var(--teal-bg)}
.gbtn.is-correct{border-color:var(--ok);background:var(--ok-bg);color:var(--ok);cursor:default}

/* Bài khóa */
.line{display:grid;grid-template-columns:auto 1fr auto;gap:4px 10px;align-items:start;padding:8px 0;border-bottom:1px solid #f0ebe3}
.line:last-child{border-bottom:0}
.sp{font-family:var(--zh);font-weight:700;color:var(--red);font-size:16px;padding-top:4px;min-width:3.5em}
.scene{font-size:14.5px;color:var(--muted);font-style:italic}

/* Ngữ pháp */
.formula{font-family:var(--zh);font-size:18px;background:var(--teal-bg);border:1px solid var(--teal-line);border-radius:10px;padding:8px 12px;margin:8px 0;font-weight:600}
.ex{display:flex;gap:8px;align-items:flex-start;padding:6px 0}
.tip{font-size:14.5px;background:#fbfaf7;border-left:4px solid var(--orange-2);padding:6px 10px;margin:8px 0}
ul.clean{margin:6px 0;padding-left:20px}
ul.clean li{margin:4px 0}
.ins{font-weight:600;margin:4px 0 8px}

/* Câu hỏi */
.q{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;margin:14px 0}
.qhead{display:flex;flex-wrap:wrap;align-items:center;gap:4px 8px;margin-bottom:6px}
.qnum{font-weight:800;color:var(--teal);margin-right:4px}
.qobj{font-size:13.5px;color:var(--muted);margin:0 0 8px}
.opts{display:grid;gap:8px;margin:10px 0}
.opt{display:flex;gap:10px;align-items:flex-start;text-align:left;border:1.5px solid var(--line);background:#fff;border-radius:12px;padding:9px 12px;color:var(--ink)}
.opt:hover:not(:disabled){border-color:var(--teal-2)}
.opt[aria-pressed="true"]{border-color:var(--teal);background:var(--teal-bg)}
.opt:disabled{cursor:default}
.opt-key{flex:none;width:26px;height:26px;border-radius:50%;display:grid;place-items:center;background:#efe9df;font-weight:700;font-size:14px;margin-top:4px}
.opt .zh{font-size:19px}
.opt.is-correct{border-color:var(--ok);background:var(--ok-bg)}
.opt.is-wrong{border-color:var(--bad);background:var(--bad-bg)}
.mark{margin-left:auto;font-size:13px;font-weight:700;white-space:nowrap;padding-top:6px}
.opt.is-correct .mark{color:var(--ok)}
.opt.is-wrong .mark{color:var(--bad)}
.fb{border-radius:12px;padding:10px 14px;margin-top:10px;font-size:15px}
.fb.ok{background:var(--ok-bg);border:1px solid #abefc6}
.fb.bad{background:var(--bad-bg);border:1px solid #fecdca}
.fb.self{background:var(--orange-bg);border:1px solid #fed7b8}
.fb-title{font-weight:800;margin:0 0 4px}
.fb.ok .fb-title{color:var(--ok)}
.fb.bad .fb-title{color:var(--bad)}
.fb p{margin:4px 0}
.zone{min-height:54px;border:2px dashed var(--teal-line);border-radius:12px;padding:8px;display:flex;flex-wrap:wrap;gap:6px;align-items:center;background:#fbfefd}
.zone:empty::before{content:attr(data-empty);color:var(--muted);font-size:14px}
.bank{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0}
.tok{font-family:var(--zh);font-size:19px;border:1.5px solid var(--teal);background:#fff;color:var(--ink);border-radius:10px;padding:5px 12px}
.tok:disabled{opacity:.3}
textarea{width:100%;font:18px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,Arial,var(--zh);border:1.5px solid var(--line);border-radius:12px;padding:10px 12px;resize:vertical;min-height:70px}
textarea:focus{border-color:var(--teal);outline:none;box-shadow:0 0 0 3px var(--teal-bg)}
details{margin:8px 0}
summary{cursor:pointer;font-weight:600;color:var(--teal)}
.player{display:flex;flex-wrap:wrap;align-items:center;gap:8px;background:var(--teal-bg);border-radius:12px;padding:8px 12px;margin:8px 0}
.crit label{display:flex;gap:8px;align-items:flex-start;margin:4px 0}
.crit input{width:18px;height:18px;margin-top:4px;accent-color:var(--teal)}
.passage{background:#fffdf9;border:1px solid #f0dfcc}

/* Kết quả */
.score{display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.score .big{font-size:44px;font-weight:800;color:var(--teal);line-height:1}
table{border-collapse:collapse;width:100%;font-size:15px}
th,td{text-align:left;padding:7px 8px;border-bottom:1px solid var(--line)}
th{color:var(--muted);font-weight:600}
.navrow{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;margin-top:22px}

/* Khung Sách bài tập */
.wb{display:block;width:100%;height:85vh;min-height:560px;border:1px solid var(--line);border-radius:var(--radius);background:#fff;margin-top:10px}

.toast{position:fixed;left:50%;bottom:18px;transform:translateX(-50%);background:#1a1a2e;color:#fff;padding:10px 16px;border-radius:10px;font-size:14.5px;max-width:92vw;opacity:0;pointer-events:none;transition:opacity .2s;z-index:20}
.toast.show{opacity:1}

@media (max-width:680px){
  .tiles{grid-template-columns:1fr;gap:10px}
  .tile{padding:12px 14px;gap:12px}
  .ti{width:48px;height:48px;border-radius:12px}
  .tl strong{font-size:16.5px}
  .hero{padding:20px 18px 16px;border-radius:18px}
  .hero-bg{font-size:140px}
  .backdrop-logo{width:56px;height:56px}
}
@media (max-width:420px){
  .sb-title{font-size:13px}
  .tg{padding:3px 9px;font-size:13px}
  h1{font-size:21px}
  .q,.card{padding:14px}
  .fc-hz{font-size:60px}
}

/* ---------- Chữ to hơn cho phần đọc (mục tiêu, đề bài, bài nói, giải thích) ---------- */
main{font-size:17.5px}
.qobj{font-size:16.5px;color:#4b5563;margin:2px 0 10px}
.ins{font-size:19px;font-weight:700;line-height:1.5}
.act>p{font-size:18.5px;line-height:1.65}
.crit p,.crit label{font-size:18px}
.crit input{width:20px;height:20px;margin-top:5px}
.badge{font-size:14px;padding:3px 11px}
.qnum{font-size:19px}
.fb{font-size:17.5px;line-height:1.6}
.fb-title{font-size:18px}
summary{font-size:18px}
ul.clean li{font-size:18px;line-height:1.6;margin:6px 0}
.card h3{font-size:19px}
.scene{font-size:16.5px}
.tip{font-size:16.5px}
.formula{font-size:20px}
.card>p{font-size:17.5px;line-height:1.65}
.opt .vi,.ex .vi,.line .vi{font-size:16px}
.py{font-size:16px}
.vi{font-size:16px}
.hz-info dd{font-size:17px}
.hz-info dt{font-size:15px}

/* ---------- Tổng kết & Ôn tập toàn khóa ---------- */
.lt-sum{border-color:var(--red)}.lt-sum .lt-n{background:var(--red)}
.sum-cta{margin:18px 0 6px}
.sum-search{flex:1;min-width:240px;font:17px/1.5 system-ui,-apple-system,"Segoe UI",Roboto,Arial,var(--zh);border:1.5px solid var(--line);border-radius:12px;padding:9px 12px}
.sum-search:focus{border-color:var(--teal);outline:none;box-shadow:0 0 0 3px var(--teal-bg)}
.sum-h2{font-size:20px;margin:22px 0 8px;color:var(--teal)}
.gsum>summary{cursor:pointer;list-style:none;font-weight:700;font-size:18px}
.gsum>summary::-webkit-details-marker{display:none}
.gsum>summary::after{content:"▾ Xem chi tiết";display:block;font-size:13px;font-weight:600;color:var(--teal);margin-top:4px}
.gsum[open]>summary::after{content:"▴ Thu gọn"}
.gsum .formula{margin:8px 0}
.selfu>summary{cursor:pointer;font-size:18px}
.selft{width:100%;border-collapse:collapse;background:#fff}
.selft th,.selft td{border:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:middle}
.selft th{background:var(--orange-bg);font-size:14px}
.selft td.c,.selft th:nth-child(n+2){text-align:center}
.selft input[type=checkbox]{width:22px;height:22px;accent-color:var(--teal)}
.selft .bar{margin-bottom:2px}

/* Chữ Việt lẫn trong khối tiếng Trung: dùng phông Latin có dấu tiếng Việt trước, phông Trung sau */
[lang|="zh"]{font-family:var(--zh)}
.kt-list .card{display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.kt-list .card h3{margin:0}
.kt-list .card .spacer{flex:1}