/* Web ôn tập HSK1 3.0 — Tiếng Trung Thu Hoài */
:root{
  --bg:#fbf5f3; --surface:#ffffff; --ink:#2a1512; --muted:#76605c; --line:#f0dfdb;
  --brand:#ac1001; --brand-2:#d8291a; --brand-deep:#7e0b01; --brand-soft:#fde8e5; --on-brand:#ffffff; --gold:#c8962e; --gold-soft:#f8efda;
  --ok:#2f7d55; --ok-soft:#e6f2ec; --mid:#b07a1e; --mid-soft:#f7efdf; --low:#c24a2c; --low-soft:#f9e6e0; --none:#c9c0be; --none-soft:#efe9e7;
  --shadow:0 1px 2px rgba(34,24,22,.05),0 8px 24px rgba(34,24,22,.06);
  --font-ui:"Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-zh:"Noto Serif SC","Songti SC","SimSun",serif;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){
  --bg:#171211; --surface:#221a19; --ink:#f3eae8; --muted:#b3a4a1; --line:#382c2a;
  --brand:#f0574a; --brand-2:#ff7a6c; --brand-deep:#7e0b01; --brand-soft:#3d1a16; --on-brand:#171211; --gold:#e2b45c; --gold-soft:#352b17;
  --ok:#5cc48f; --ok-soft:#18301f; --mid:#e2b45c; --mid-soft:#352b17; --low:#ef8a6c; --low-soft:#3a201a; --none:#5c4f4d; --none-soft:#2b2221;
  --shadow:0 1px 2px rgba(0,0,0,.3),0 8px 24px rgba(0,0,0,.25); color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#171211; --surface:#221a19; --ink:#f3eae8; --muted:#b3a4a1; --line:#382c2a;
  --brand:#f0574a; --brand-2:#ff7a6c; --brand-deep:#7e0b01; --brand-soft:#3d1a16; --on-brand:#171211; --gold:#e2b45c; --gold-soft:#352b17;
  --ok:#5cc48f; --ok-soft:#18301f; --mid:#e2b45c; --mid-soft:#352b17; --low:#ef8a6c; --low-soft:#3a201a; --none:#5c4f4d; --none-soft:#2b2221;
  --shadow:0 1px 2px rgba(0,0,0,.3),0 8px 24px rgba(0,0,0,.25); color-scheme:dark}
[hidden]{display:none!important}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font-ui);font-size:16px;line-height:1.55;min-height:100vh}
a{color:var(--brand)}
.zh{font-family:var(--font-zh)}
.wrap{max-width:760px;margin:0 auto;padding-block:16px 72px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px));display:grid;gap:18px}
.wrap.wide{max-width:1080px}
/* đầu trang */
.topbar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:inherit;min-width:0}
.logo img{width:46px;height:46px;border-radius:50%;flex:none;box-shadow:0 2px 8px rgba(168,32,26,.25)}
.logo b{display:block;font-weight:800;letter-spacing:.05em;font-size:14px;color:var(--brand);line-height:1.2}
.logo span{display:block;font-family:var(--font-zh);color:var(--muted);font-size:13px;line-height:1.3}
.who{display:flex;align-items:center;gap:8px;font-size:14px;color:var(--muted)}
.avatar{width:36px;height:36px;border-radius:50%;background:var(--brand-soft);color:var(--brand);display:grid;place-items:center;font-weight:800;font-size:15px;flex:none}
.menu{position:relative}
.menu>button{border:1px solid var(--line);background:var(--surface);color:var(--ink);border-radius:999px;padding:4px 12px 4px 4px;display:flex;align-items:center;gap:8px;font:600 14px var(--font-ui);cursor:pointer}
.menu .drop{position:absolute;right:0;top:calc(100% + 6px);background:var(--surface);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);padding:6px;min-width:210px;z-index:40;display:grid}
.menu .drop button,.menu .drop a{border:0;background:none;text-align:left;padding:10px 12px;border-radius:10px;font:500 14px var(--font-ui);color:var(--ink);cursor:pointer;text-decoration:none}
.menu .drop button:hover,.menu .drop a:hover{background:var(--bg)}
button:focus-visible,a:focus-visible,summary:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:2px solid var(--brand);outline-offset:2px}
/* khối */
.card{background:var(--surface);border:1px solid var(--line);border-radius:20px;padding:22px;min-width:0;box-shadow:var(--shadow)}
.card.flat{box-shadow:none}
h1,h2,h3{margin:0;text-wrap:balance}
h2{font-size:19px;font-weight:700;margin-bottom:4px}
.sub{margin:0 0 14px;color:var(--muted);font-size:14px}
.h3{font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:0 0 8px}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.spread{display:flex;justify-content:space-between;gap:12px;align-items:center;flex-wrap:wrap}
.muted{color:var(--muted)}
.small{font-size:13px}
/* nút */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:12px;background:var(--brand);color:var(--on-brand);font:700 15px var(--font-ui);padding:12px 20px;cursor:pointer;white-space:nowrap;text-decoration:none;transition:transform .12s ease, filter .12s ease}
.btn:hover{filter:brightness(1.06)}
.btn:active{transform:translateY(1px) scale(.99)}
.btn[disabled]{opacity:.5;cursor:not-allowed}
.btn.small{font-size:14px;padding:8px 14px;border-radius:10px}
.btn.line{background:transparent;color:var(--brand);border:1.5px solid var(--brand)}
.btn.ghost{background:var(--bg);color:var(--ink);border:1px solid var(--line)}
.btn.ok{background:var(--ok)}
.btn.big{font-size:17px;padding:15px 26px;border-radius:14px}
.btn.block{width:100%}
/* biểu mẫu */
label.f{display:grid;gap:5px;font-size:13px;font-weight:600;color:var(--muted)}
input[type=text],input[type=email],input[type=password],input[type=date],input[type=search],select,textarea{font:15px var(--font-ui);color:var(--ink);background:var(--surface);border:1.5px solid var(--line);border-radius:12px;padding:11px 13px;width:100%;max-width:100%}
input:focus,select:focus,textarea:focus{border-color:var(--brand);outline:none}
textarea{min-height:76px;resize:vertical}
.form{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.form .full{grid-column:1/-1}
.err{color:var(--low);font-size:14px;min-height:20px;margin:0}
/* thanh / nhãn */
.track{height:10px;border-radius:999px;background:var(--none-soft);overflow:hidden}
.track i{display:block;height:100%;border-radius:999px;width:0}
.c-ok{background:var(--ok)}.c-mid{background:var(--mid)}.c-low{background:var(--low)}.c-none{background:var(--none-soft)}.c-brand{background:var(--brand)}
.t-ok{color:var(--ok)}.t-mid{color:var(--mid)}.t-low{color:var(--low)}.t-none{color:var(--muted)}
.legend{display:flex;flex-wrap:wrap;gap:6px 16px;font-size:13px;color:var(--muted);margin-top:12px}
.legend i{display:inline-block;width:10px;height:10px;border-radius:50%;margin-right:6px;vertical-align:-1px}
.pill{display:inline-flex;align-items:center;gap:6px;font-size:13px;font-weight:700;padding:5px 12px;border-radius:999px;background:var(--bg);border:1px solid var(--line);white-space:nowrap}
.pill.fire{color:var(--low);background:var(--low-soft);border-color:transparent}
.pill.rank{color:var(--brand);background:var(--brand-soft);border-color:transparent}
.pill.gold{color:var(--gold);background:var(--gold-soft);border-color:transparent}
.tag{display:inline-block;font-size:12px;font-weight:700;padding:3px 10px;border-radius:999px;white-space:nowrap}
.tag.todo{background:var(--low-soft);color:var(--low)}.tag.wait{background:var(--mid-soft);color:var(--mid)}.tag.done{background:var(--ok-soft);color:var(--ok)}.tag.none{background:var(--none-soft);color:var(--muted)}
.tag.new{background:var(--brand);color:var(--on-brand);font-size:11px;vertical-align:2px}
/* vòng % */
.ring{position:relative;width:156px;height:156px;flex:none}
.ring svg{width:100%;height:100%;transform:rotate(-90deg)}
.ring .num{position:absolute;inset:0;display:grid;place-items:center;text-align:center}
.ring b{font-size:44px;font-weight:800;line-height:1;font-variant-numeric:tabular-nums}
.ring small{display:block;color:var(--muted);font-size:13px;margin-top:4px;font-weight:600;letter-spacing:.06em}
@media (prefers-reduced-motion:no-preference){.track i,.ring .v{transition:all .9s cubic-bezier(.2,.8,.2,1)}}
/* danh sách */
.list>*{padding:12px 0;border-bottom:1px solid var(--line)}
.list>*:last-child{border-bottom:0}
.empty{color:var(--muted);font-size:14px;text-align:center;padding:18px 8px;background:var(--bg);border-radius:14px}
/* hộp thoại */
.modal{position:fixed;inset:0;background:rgba(20,12,11,.55);display:grid;place-items:center;padding:16px;z-index:50}
.sheet{background:var(--surface);color:var(--ink);border-radius:22px;max-width:520px;width:100%;padding:22px;display:grid;gap:14px;max-height:92vh;overflow:auto;box-shadow:0 20px 60px rgba(0,0,0,.3)}
.sheet.wide{max-width:680px}
.sheet h3{font-size:18px}
.toast{position:fixed;left:50%;bottom:calc(22px + env(safe-area-inset-bottom,0px));transform:translateX(-50%);background:var(--ink);color:var(--bg);padding:11px 20px;border-radius:999px;font-size:14px;font-weight:600;z-index:80;max-width:92vw;text-align:center;box-shadow:0 8px 24px rgba(0,0,0,.25)}
/* tab */
.tabs{display:flex;gap:4px;overflow-x:auto;scrollbar-width:none;border-bottom:1px solid var(--line);padding-bottom:8px}
.tabs::-webkit-scrollbar{display:none}
.tabs button{border:0;background:transparent;font:600 15px var(--font-ui);color:var(--muted);padding:9px 13px;border-radius:10px;cursor:pointer;white-space:nowrap;flex:none}
.tabs button[aria-selected="true"]{color:var(--ink);background:var(--surface);box-shadow:0 0 0 1px var(--line)}
.tabs .cnt{font-size:11px;background:var(--low);color:#fff;border-radius:999px;padding:1px 7px;margin-left:4px}
.filters{display:flex;gap:8px;flex-wrap:wrap;margin:4px 0 12px}
.filters button{border:1.5px solid var(--line);background:var(--surface);color:var(--ink);border-radius:999px;padding:6px 14px;font:600 14px var(--font-ui);cursor:pointer}
.filters button[aria-pressed="true"]{border-color:var(--ink);background:var(--ink);color:var(--bg)}
.sw{display:flex;gap:10px;align-items:center;font-size:14px;cursor:pointer}
.sw input{appearance:none;-webkit-appearance:none;width:40px;height:23px;border-radius:999px;background:var(--none);position:relative;flex:none;cursor:pointer;transition:background .2s;margin:0}
.sw input::after{content:"";position:absolute;top:3px;left:3px;width:17px;height:17px;border-radius:50%;background:#fff;transition:left .2s}
.sw input:checked{background:var(--ok)}
.sw input:checked::after{left:20px}
/* nền chữ Hán bay */
.floaty{position:fixed;inset:0;pointer-events:none;overflow:hidden;z-index:0}
.floaty span{position:absolute;font-family:var(--font-zh);color:var(--brand);opacity:.06;font-weight:700;user-select:none}
@media (prefers-reduced-motion:no-preference){.floaty span{animation:drift 22s ease-in-out infinite alternate}}
@keyframes drift{from{transform:translateY(0) rotate(-6deg)}to{transform:translateY(-40px) rotate(6deg)}}
.above{position:relative;z-index:1}
/* hiệu ứng nhỏ */
@media (prefers-reduced-motion:no-preference){
  .pop{animation:pop .35s cubic-bezier(.2,1.4,.4,1)}
  @keyframes pop{from{transform:scale(.85);opacity:0}to{transform:scale(1);opacity:1}}
  .shake{animation:shake .35s}
  @keyframes shake{20%,60%{transform:translateX(-6px)}40%,80%{transform:translateX(6px)}}
}
.confetti{position:fixed;inset:0;pointer-events:none;z-index:90}
.footer{text-align:center;color:var(--muted);font-size:13px;padding-top:6px}
.footer .zh{color:var(--brand)}
@media (max-width:560px){.form{grid-template-columns:1fr}.card{padding:18px;border-radius:18px}.ring{width:140px;height:140px}.ring b{font-size:40px}}

/* ====== màu logo: dải đỏ đầu trang + vòng tròn như con dấu ====== */
body.band{--band:220px}
body.band::before{content:"";position:absolute;left:0;right:0;top:0;height:var(--band);z-index:0;
  background:
    radial-gradient(circle at 88% 30%, transparent 0 96px, rgba(255,255,255,.16) 97px 100px, transparent 101px 128px, rgba(255,255,255,.10) 129px 131px, transparent 132px),
    radial-gradient(circle at 6% 120%, rgba(255,255,255,.10) 0 120px, transparent 121px),
    linear-gradient(135deg,var(--brand-2) 0%,#ac1001 50%,var(--brand-deep) 100%);
  border-radius:0 0 34px 34px}
body.band::after{content:"怀";position:absolute;right:max(16px,calc(50% - 520px));top:calc(var(--band) - 168px);font:700 120px/1 var(--font-zh);color:rgba(255,255,255,.13);z-index:0;pointer-events:none}
body.band .topbar .logo b{color:#fff}
body.band .topbar .logo span{color:rgba(255,255,255,.85)}
body.band .topbar .logo img{box-shadow:0 0 0 3px rgba(255,255,255,.9),0 6px 18px rgba(0,0,0,.25)}
body.band .menu>button{border-color:transparent;box-shadow:0 4px 14px rgba(0,0,0,.18)}
body.band .bandtitle{color:#fff;margin:4px 0 -4px}
body.band .bandtitle h1{font-size:24px}
body.band .bandtitle p{margin:2px 0 0;color:rgba(255,255,255,.85);font-size:14px}
.btn:not(.line):not(.ghost):not(.ok){background:linear-gradient(135deg,var(--brand-2),var(--brand));box-shadow:0 4px 14px rgba(172,16,1,.28)}
.card{border-color:var(--line)}
.h3{color:var(--brand)}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) body.band::before{background:linear-gradient(135deg,#8a1408,#4a0802);}}
:root[data-theme="dark"] body.band::before{background:linear-gradient(135deg,#8a1408,#4a0802)}
@media (max-width:560px){body.band{--band:180px}body.band::after{font-size:90px;top:calc(var(--band) - 120px)}}

/* thanh tab dạng viên thuốc, đọc rõ trên cả nền đỏ lẫn nền sáng */
.tabs{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:6px;box-shadow:var(--shadow)}
.tabs button[aria-selected="true"]{background:linear-gradient(135deg,var(--brand-2),var(--brand));color:#fff;box-shadow:0 3px 10px rgba(172,16,1,.3)}
.tabs button[aria-selected="true"] .cnt{background:#fff;color:var(--brand)}