/* =====================================================================
 * 600CÂU — Ôn thi GPLX & Tiện ích giao thông
 * Design language: BIỂN BÁO GIAO THÔNG (traffic-sign vernacular)
 *   xanh hiệu lệnh · đỏ cấm · vàng cảnh báo · xanh lá "đạt"
 * Mobile-first · Core Web Vitals · a11y · reduced-motion
 * ===================================================================== */

:root{
  /* Palette lấy từ biển báo thật */
  --blue:#0B5FB0;          /* biển hiệu lệnh — thương hiệu, tin cậy */
  --blue-deep:#073E73;
  --blue-mist:#EAF2FB;
  --red:#D32C2C;           /* biển cấm — phạt, nguy hiểm, sai */
  --red-deep:#A81E1E;
  --red-mist:#FCEBEB;
  --amber:#F5A623;         /* biển cảnh báo — nhấn mạnh, CTA phụ */
  --amber-deep:#C77F12;
  --amber-soft:#FEF3DD;
  --green:#1E9E5A;         /* đạt / đúng */
  --green-mist:#E6F5EC;
  --ink:#15202B;
  --ink-soft:#475569;
  --muted:#8A97A6;
  --line:#E2E8F0;
  --paper:#FFFFFF;
  --mist:#F2F6FB;          /* nền mát kiểu app */

  --shadow-sm:0 1px 2px rgba(21,32,43,.06);
  --shadow:0 4px 14px rgba(21,32,43,.10);
  --shadow-lg:0 14px 40px rgba(21,32,43,.16);
  --radius:16px;
  --radius-sm:10px;
  --maxw:1080px;

  --font-display:"Barlow Semi Condensed",system-ui,sans-serif;
  --font-body:"Be Vietnam Pro",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;font-family:var(--font-body);font-size:16px;line-height:1.6;
  color:var(--ink);background:var(--mist);-webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
img,svg{max-width:100%;display:block}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:800;line-height:1.05;margin:0 0 .4em;letter-spacing:-.01em}
h1{font-size:clamp(2rem,7vw,3.1rem)}
h2{font-size:clamp(1.55rem,5vw,2.2rem)}
h3{font-size:1.18rem;font-weight:700}
p{margin:.8em 0}

.wrap{max-width:var(--maxw);margin:0 auto;padding:0 16px}
.eyebrow{font-family:var(--font-body);font-size:.72rem;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--blue);display:inline-block}

/* sign-label: nhãn kiểu biển báo */
.sign-label{display:inline-flex;align-items:center;gap:7px;font-family:var(--font-body);font-weight:700;font-size:.7rem;letter-spacing:.12em;text-transform:uppercase;padding:5px 12px;border-radius:30px}
.sign-label.blue{background:var(--blue-mist);color:var(--blue-deep)}
.sign-label.red{background:var(--red-mist);color:var(--red-deep)}
.sign-label.amber{background:var(--amber-soft);color:var(--amber-deep)}
.sign-label.green{background:var(--green-mist);color:var(--green)}

/* ============ HEADER ============ */
.hdr{position:sticky;top:0;z-index:100;background:var(--paper);border-bottom:1px solid var(--line);box-shadow:var(--shadow-sm)}
.hdr .wrap{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{display:flex;align-items:center;gap:10px;color:var(--ink)}
.brand:hover{text-decoration:none}
.brand-mark{width:38px;height:38px;flex:none}
.brand-name{font-family:var(--font-display);font-weight:800;font-size:1.45rem;line-height:1;letter-spacing:-.02em}
.brand-name b{color:var(--blue)}
.brand-name small{display:block;font-family:var(--font-body);font-weight:500;font-size:.6rem;letter-spacing:.08em;color:var(--muted);text-transform:uppercase;margin-top:2px}
.nav-btn{display:flex;align-items:center;justify-content:center;width:42px;height:40px;border:1px solid var(--line);border-radius:10px;background:var(--paper);cursor:pointer;color:var(--ink)}
.nav{display:none;position:absolute;top:60px;left:0;right:0;background:var(--paper);border-bottom:1px solid var(--line);box-shadow:var(--shadow);padding:6px 0}
.nav.open{display:block}
.nav a{display:block;padding:13px 20px;color:var(--ink);font-weight:600;border-bottom:1px solid var(--mist)}
.nav a:hover{background:var(--blue-mist);text-decoration:none}
@media(min-width:860px){
  .nav-btn{display:none}
  .nav{display:flex;position:static;border:none;box-shadow:none;padding:0;gap:2px;background:none}
  .nav a{padding:9px 14px;border:none;border-radius:9px;font-size:.95rem}
}

/* ============ HERO ============ */
.hero{background:linear-gradient(168deg,var(--blue) 0%,var(--blue-deep) 100%);color:#fff;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;right:-60px;top:-60px;width:280px;height:280px;border-radius:50%;border:30px solid rgba(255,255,255,.05)}
.hero .wrap{position:relative;z-index:1;padding:38px 16px 44px}
.hero .eyebrow{color:var(--amber)}
.hero h1{color:#fff;margin-top:10px;max-width:13ch}
.hero p.sub{font-size:1.08rem;color:#D6E6F6;max-width:46ch;margin:12px 0 0}
.hero-cta{display:flex;flex-wrap:wrap;gap:12px;margin-top:24px}
.trust-row{display:flex;flex-wrap:wrap;gap:8px 18px;margin-top:22px;font-size:.84rem;color:#BFD7EF}
.trust-row span{display:inline-flex;align-items:center;gap:6px}
.trust-row svg{width:15px;height:15px;flex:none}

/* ============ BUTTONS ============ */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;font-family:var(--font-body);font-weight:700;font-size:1rem;padding:14px 24px;border-radius:12px;border:none;cursor:pointer;transition:transform .12s,box-shadow .12s,background .12s;text-decoration:none;line-height:1}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-amber{background:var(--amber);color:#3a2a00;box-shadow:0 6px 16px rgba(245,166,35,.4)}
.btn-amber:hover{background:#ffb733}
.btn-white{background:#fff;color:var(--blue-deep)}
.btn-white:hover{background:#eef4fb}
.btn-blue{background:var(--blue);color:#fff}
.btn-blue:hover{background:var(--blue-deep)}
.btn-ghost{background:transparent;color:#fff;box-shadow:inset 0 0 0 1.5px rgba(255,255,255,.5)}
.btn-ghost:hover{background:rgba(255,255,255,.1)}
.btn-lg{padding:16px 30px;font-size:1.08rem}
.btn-block{display:flex;width:100%}

/* ============ SIGN CARDS (signature) ============ */
.signs{display:grid;gap:14px;grid-template-columns:1fr;margin-top:-30px;position:relative;z-index:5}
@media(min-width:680px){.signs{grid-template-columns:repeat(3,1fr)}}
.sign-card{background:var(--paper);border-radius:var(--radius);padding:22px 20px;box-shadow:var(--shadow);border:1px solid var(--line);display:flex;flex-direction:column;transition:transform .15s,box-shadow .15s}
.sign-card:hover{text-decoration:none;transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.sign-ico{width:60px;height:60px;margin-bottom:14px;flex:none}
.sign-card h3{color:var(--ink);font-size:1.3rem;margin-bottom:4px}
.sign-card p{color:var(--ink-soft);font-size:.92rem;margin:0;flex:1}
.sign-card .go{margin-top:14px;font-weight:700;font-size:.92rem;display:inline-flex;align-items:center;gap:6px}
.sign-card.c-blue .go{color:var(--blue)}
.sign-card.c-red .go{color:var(--red)}
.sign-card.c-amber .go{color:var(--amber-deep)}

/* ============ SECTION ============ */
.sec{padding:44px 0}
.sec-head{margin-bottom:22px}
.sec-head h2{margin-top:6px}
.sec-head p{color:var(--ink-soft);margin:6px 0 0;max-width:56ch}
.sec.alt{background:var(--paper);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}

/* ============ HẠNG CHIPS ============ */
.hang-row{display:flex;flex-wrap:wrap;gap:10px}
.hang-chip{display:flex;flex-direction:column;align-items:center;gap:2px;padding:14px 8px;background:var(--paper);border:1.5px solid var(--line);border-radius:14px;cursor:pointer;flex:1;min-width:84px;transition:border-color .12s,transform .12s;color:var(--ink)}
.hang-chip:hover{border-color:var(--blue);transform:translateY(-2px);text-decoration:none}
.hang-chip b{font-family:var(--font-display);font-size:1.5rem;font-weight:800;color:var(--blue)}
.hang-chip span{font-size:.78rem;color:var(--ink-soft);text-align:center}

/* ============ FINE QUICK CARDS ============ */
.fine-grid{display:grid;gap:12px;grid-template-columns:1fr;margin-top:4px}
@media(min-width:560px){.fine-grid{grid-template-columns:1fr 1fr}}
@media(min-width:900px){.fine-grid{grid-template-columns:repeat(4,1fr)}}
.fine-card{background:var(--paper);border:1px solid var(--line);border-left:4px solid var(--red);border-radius:12px;padding:16px;transition:transform .12s,box-shadow .12s;color:var(--ink)}
.fine-card:hover{text-decoration:none;transform:translateY(-3px);box-shadow:var(--shadow)}
.fine-card .lbl{font-size:.82rem;color:var(--ink-soft);font-weight:600}
.fine-card .amt{font-family:var(--font-display);font-weight:800;font-size:1.5rem;color:var(--red-deep);margin:4px 0 2px;line-height:1.05}
.fine-card .meta{font-size:.76rem;color:var(--muted)}

/* ============ FEATURE (vì sao) ============ */
.feat-grid{display:grid;gap:16px;grid-template-columns:1fr}
@media(min-width:680px){.feat-grid{grid-template-columns:repeat(3,1fr)}}
.feat{padding:4px}
.feat .fico{width:46px;height:46px;border-radius:12px;background:var(--blue-mist);display:grid;place-items:center;margin-bottom:12px}
.feat .fico svg{width:24px;height:24px;stroke:var(--blue);fill:none;stroke-width:1.8}
.feat h3{margin-bottom:4px}
.feat p{color:var(--ink-soft);font-size:.94rem;margin:0}

/* ============ POST CARDS ============ */
.post-grid{display:grid;gap:14px;grid-template-columns:1fr}
@media(min-width:620px){.post-grid{grid-template-columns:1fr 1fr}}
.post{background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:18px;color:var(--ink);transition:transform .12s,box-shadow .12s}
.post:hover{text-decoration:none;transform:translateY(-3px);box-shadow:var(--shadow)}
.post h3{margin:8px 0 4px}
.post p{color:var(--ink-soft);font-size:.9rem;margin:0}

/* ============ QUIZ ENGINE ============ */
.quiz-shell{max-width:680px;margin:0 auto}
.quiz-top{display:flex;align-items:center;justify-content:space-between;gap:12px;background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:12px 16px;margin-bottom:14px;position:sticky;top:68px;z-index:20}
.quiz-prog{font-size:.88rem;color:var(--ink-soft);font-weight:600}
.quiz-prog b{color:var(--ink);font-family:var(--font-display);font-size:1.1rem}
/* timer kiểu biển tốc độ */
.timer{display:flex;align-items:center;gap:8px;font-weight:700;font-family:var(--font-display);font-size:1.2rem}
.timer-ring{width:34px;height:34px;border-radius:50%;border:4px solid var(--red);display:grid;place-items:center;font-size:.62rem;color:var(--red);background:#fff}
.timer.warn{color:var(--red)}
.qbar{height:6px;background:var(--line);border-radius:30px;overflow:hidden;margin-bottom:16px}
.qbar i{display:block;height:100%;background:var(--blue);border-radius:30px;transition:width .25s}
.qcard{background:var(--paper);border:1px solid var(--line);border-radius:16px;padding:22px;box-shadow:var(--shadow-sm)}
.qcat{font-size:.74rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--blue)}
.qcat.liet{color:var(--red)}
.qtext{font-size:1.15rem;font-weight:600;margin:8px 0 16px;line-height:1.45}
.qimg{border-radius:12px;border:1px solid var(--line);margin:0 0 16px;width:100%}
.opts{display:flex;flex-direction:column;gap:10px}
.opt{display:flex;gap:12px;align-items:flex-start;padding:14px 16px;border:1.5px solid var(--line);border-radius:12px;cursor:pointer;background:var(--paper);transition:border-color .12s,background .12s;font-size:1rem;text-align:left;width:100%;font-family:inherit;color:var(--ink)}
.opt:hover{border-color:var(--blue);background:var(--blue-mist)}
.opt .num{flex:none;width:26px;height:26px;border-radius:7px;background:var(--mist);display:grid;place-items:center;font-weight:700;font-size:.85rem;color:var(--ink-soft)}
.opt.sel{border-color:var(--blue);background:var(--blue-mist)}
.opt.sel .num{background:var(--blue);color:#fff}
.opt.correct{border-color:var(--green);background:var(--green-mist)}
.opt.correct .num{background:var(--green);color:#fff}
.opt.wrong{border-color:var(--red);background:var(--red-mist)}
.opt.wrong .num{background:var(--red);color:#fff}
.qexplain{margin-top:14px;padding:14px 16px;background:var(--amber-soft);border-radius:12px;font-size:.92rem;color:#5a4413;display:none}
.qexplain.show{display:block}
.qexplain b{color:var(--amber-deep)}
.quiz-nav{display:flex;gap:10px;margin-top:18px}
.quiz-nav .btn{flex:1}
.qdots{display:flex;flex-wrap:wrap;gap:5px;margin-top:16px;justify-content:center}
.qdot{width:26px;height:26px;border-radius:7px;border:1px solid var(--line);background:var(--paper);font-size:.74rem;font-weight:600;color:var(--ink-soft);cursor:pointer;display:grid;place-items:center}
.qdot.answered{background:var(--blue);color:#fff;border-color:var(--blue)}
.qdot.current{outline:2px solid var(--amber);outline-offset:1px}
.qdot.flag{background:var(--amber);color:#3a2a00;border-color:var(--amber)}

/* kết quả thi */
.result{background:var(--paper);border:1px solid var(--line);border-radius:18px;padding:28px;text-align:center;box-shadow:var(--shadow)}
.result .score{font-family:var(--font-display);font-weight:800;font-size:3.4rem;line-height:1}
.result.pass .score{color:var(--green)}
.result.fail .score{color:var(--red)}
.result .verdict{font-family:var(--font-display);font-weight:800;font-size:1.6rem;margin:6px 0}
.result.pass .verdict{color:var(--green)}
.result.fail .verdict{color:var(--red)}
.result .detail{color:var(--ink-soft);font-size:.95rem}
.result-actions{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-top:20px}

/* ============ MODE SELECT ============ */
.mode-grid{display:grid;gap:14px;grid-template-columns:1fr}
@media(min-width:560px){.mode-grid{grid-template-columns:1fr 1fr}}
.mode-card{background:var(--paper);border:1.5px solid var(--line);border-radius:16px;padding:22px;cursor:pointer;transition:border-color .12s,transform .12s;color:var(--ink)}
.mode-card:hover{border-color:var(--blue);transform:translateY(-3px);text-decoration:none}
.mode-card h3{margin:10px 0 4px}
.mode-card p{color:var(--ink-soft);font-size:.9rem;margin:0}

/* ============ PENALTY LOOKUP ============ */
.lookup{background:var(--paper);border:1px solid var(--line);border-radius:16px;padding:18px;box-shadow:var(--shadow-sm);margin-bottom:20px}
.lookup .row{display:grid;gap:10px;grid-template-columns:1fr}
@media(min-width:620px){.lookup .row{grid-template-columns:1fr 1fr}}
.field label{display:block;font-weight:600;font-size:.88rem;margin-bottom:5px}
.field select,.field input{width:100%;padding:12px 14px;border:1.5px solid var(--line);border-radius:11px;font-size:1rem;font-family:inherit;background:var(--paper);color:var(--ink)}
.field select:focus,.field input:focus{outline:none;border-color:var(--blue);box-shadow:0 0 0 3px rgba(11,95,176,.14)}
.search-box{position:relative}
.search-box input{padding-left:42px}
.search-box svg{position:absolute;left:14px;top:50%;transform:translateY(-50%);width:18px;height:18px;stroke:var(--muted);fill:none;stroke-width:2}

/* bảng phạt */
.fine-list{display:flex;flex-direction:column;gap:12px}
.fine-item{background:var(--paper);border:1px solid var(--line);border-radius:14px;overflow:hidden}
.fine-item summary{padding:16px 18px;cursor:pointer;display:flex;align-items:center;justify-content:space-between;gap:12px;list-style:none}
.fine-item summary::-webkit-details-marker{display:none}
.fine-item .fi-name{font-weight:600;flex:1}
.fine-item .fi-amt{font-family:var(--font-display);font-weight:800;color:var(--red-deep);font-size:1.1rem;white-space:nowrap;text-align:right}
.fine-item .fi-amt small{display:block;font-family:var(--font-body);font-weight:500;font-size:.68rem;color:var(--muted)}
.fine-item .fi-body{padding:0 18px 16px;border-top:1px solid var(--line);font-size:.92rem;color:var(--ink-soft)}
.fine-item .fi-body dl{display:grid;grid-template-columns:auto 1fr;gap:6px 14px;margin:14px 0 0}
.fine-item .fi-body dt{font-weight:600;color:var(--ink)}
.fine-item .penalty-extra{display:inline-block;margin-top:10px;padding:4px 11px;border-radius:20px;background:var(--red-mist);color:var(--red-deep);font-size:.8rem;font-weight:600;margin-right:6px}
.fine-item .penalty-extra.pts{background:var(--amber-soft);color:var(--amber-deep)}
.no-result{text-align:center;color:var(--muted);padding:30px}

/* ============ ĐĂNG KIỂM CALC ============ */
.dk-result{margin-top:18px;display:none}
.dk-result.show{display:block}
.dk-big{background:linear-gradient(160deg,var(--blue),var(--blue-deep));color:#fff;border-radius:16px;padding:24px;text-align:center}
.dk-big .when{font-family:var(--font-display);font-weight:800;font-size:2.2rem;margin:6px 0}
.dk-big .days{font-size:1rem;color:#D6E6F6}
.dk-note{margin-top:12px;padding:14px 16px;border-radius:12px;font-size:.9rem}
.dk-note.ok{background:var(--green-mist);color:var(--green)}
.dk-note.warn{background:var(--amber-soft);color:var(--amber-deep)}
.dk-note.over{background:var(--red-mist);color:var(--red-deep)}

/* ============ ARTICLE ============ */
.article{background:var(--paper);border:1px solid var(--line);border-radius:16px;padding:24px;box-shadow:var(--shadow-sm)}
.article h2{margin-top:1.4em}
.article h2:first-child{margin-top:0}
.article ul,.article ol{padding-left:22px}
.article li{margin:6px 0}
.article table{width:100%;border-collapse:collapse;margin:16px 0;font-size:.92rem}
.article th,.article td{padding:10px 12px;border:1px solid var(--line);text-align:left}
.article th{background:var(--blue-mist);color:var(--blue-deep)}
.article blockquote{border-left:4px solid var(--amber);background:var(--amber-soft);margin:16px 0;padding:12px 16px;border-radius:0 10px 10px 0;color:#5a4413}
.lead{font-size:1.1rem;color:var(--ink-soft)}

/* ============ BREADCRUMB ============ */
.crumb{font-size:.84rem;color:var(--muted);padding:14px 0 0}
.crumb a{color:var(--ink-soft)}
.crumb b{color:var(--ink)}

/* ============ DISCLAIMER ============ */
.note{background:var(--blue-mist);border:1px solid #cfe1f5;border-radius:12px;padding:14px 16px;font-size:.88rem;color:var(--ink-soft);margin:20px 0}
.note b{color:var(--blue-deep)}

/* ============ FOOTER ============ */
.ftr{background:var(--ink);color:#C7D2DE;padding:40px 0 20px;margin-top:50px}
.ftr h4{font-family:var(--font-body);color:#fff;font-size:.82rem;letter-spacing:.08em;text-transform:uppercase;margin:0 0 12px}
.ftr a{color:#9FB0C0;display:block;padding:4px 0;font-size:.92rem}
.ftr a:hover{color:#fff}
.ftr-cols{display:grid;gap:26px;grid-template-columns:1fr 1fr}
@media(min-width:760px){.ftr-cols{grid-template-columns:2fr 1fr 1fr 1fr}}
.ftr-brand .brand-name{color:#fff}
.ftr-brand p{font-size:.88rem;color:#8595A5;margin:10px 0 0;max-width:34ch}
.ftr-bottom{border-top:1px solid #243240;margin-top:28px;padding-top:16px;font-size:.82rem;color:#6B7B8C;text-align:center}

/* ============ UTIL ============ */
.center{text-align:center}
.mt0{margin-top:0}
.hide{display:none}
.spin{width:34px;height:34px;border:3px solid var(--line);border-top-color:var(--blue);border-radius:50%;animation:sp 1s linear infinite;margin:30px auto}
@keyframes sp{to{transform:rotate(360deg)}}

/* ============ A11Y ============ */
:focus-visible{outline:3px solid var(--amber);outline-offset:2px;border-radius:6px}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}