:root{--bg:#f5f7fb;--surface:#fff;--surface2:#eef2f7;--text:#101828;--muted:#667085;--line:#e4e7ec;--primary:#111827;--accent:#f4b400;--danger:#d92d20;--success:#079455;--shadow:0 10px 30px rgba(16,24,40,.08);--radius:18px}
[data-theme="dark"]{--bg:#08101f;--surface:#101827;--surface2:#182235;--text:#f6f8fb;--muted:#9ca8bb;--line:#26334a;--primary:#f9fafb;--accent:#f5c542;--danger:#f97066;--success:#32d583;--shadow:0 10px 30px rgba(0,0,0,.3)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Noto Sans Bengali",Arial,sans-serif;background:var(--bg);color:var(--text)}button,input,select,textarea{font:inherit}.sidebar{position:fixed;inset:0 auto 0 0;width:260px;background:#0f172a;color:#fff;padding:22px 16px;display:flex;flex-direction:column;z-index:20}.brand{display:flex;align-items:center;gap:12px;padding:0 8px 18px}.brand-mark{width:42px;height:42px;border-radius:13px;display:grid;place-items:center;font-weight:900;background:linear-gradient(180deg,#111 0 33%,#d00 33% 66%,#ffce00 66%);border:1px solid rgba(255,255,255,.12)}.brand strong{display:block;font-size:20px}.brand span{display:block;font-size:12px;color:#94a3b8}.nav{display:grid;gap:5px}.nav-item{border:0;background:transparent;color:#cbd5e1;padding:11px 12px;border-radius:12px;text-align:left;cursor:pointer;display:flex;gap:10px;align-items:center}.nav-item:hover,.nav-item.active{background:#1e293b;color:#fff}.sidebar-footer{margin-top:auto}.sidebar-footer small{display:block;color:#64748b;text-align:center;margin-top:12px}.level-switch{display:grid;grid-template-columns:repeat(3,1fr);background:#111827;border:1px solid #334155;border-radius:12px;padding:4px;gap:4px}.level-switch button{border:0;background:transparent;color:#94a3b8;padding:8px;border-radius:9px;cursor:pointer}.level-switch button.active{background:#f8fafc;color:#0f172a;font-weight:800}.main{margin-left:260px;min-height:100vh}.topbar{position:sticky;top:0;z-index:10;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(14px);display:flex;align-items:center;gap:16px;padding:18px 28px;border-bottom:1px solid var(--line)}.topbar h1{margin:0;font-size:23px}.topbar p{margin:3px 0 0;color:var(--muted);font-size:13px}.top-actions{margin-left:auto;display:flex;align-items:center;gap:10px}.icon-btn{border:1px solid var(--line);background:var(--surface);color:var(--text);width:40px;height:40px;border-radius:12px;cursor:pointer}.mobile-menu{display:none}.streak-pill{background:var(--surface);border:1px solid var(--line);padding:8px 11px;border-radius:999px;font-size:13px}.content{padding:28px;max-width:1500px;margin:auto}.hero{background:linear-gradient(135deg,#101828,#344054);color:#fff;border-radius:26px;padding:30px;display:grid;grid-template-columns:1.35fr .65fr;gap:24px;overflow:hidden;box-shadow:var(--shadow)}.hero h2{font-size:32px;margin:0 0 10px}.hero p{color:#d0d5dd;max-width:760px;line-height:1.7}.hero-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}.btn{border:0;border-radius:12px;padding:11px 16px;cursor:pointer;font-weight:750}.btn-primary{background:#f4b400;color:#111827}.btn-dark{background:#101828;color:#fff}.btn-light{background:var(--surface);color:var(--text);border:1px solid var(--line)}.btn-ghost{background:transparent;border:1px solid rgba(255,255,255,.22);color:#fff}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:18px 0}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.stat{padding:17px}.stat .label{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}.stat .value{font-size:27px;font-weight:900;margin-top:4px}.grid{display:grid;gap:16px}.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}.section-head{display:flex;align-items:end;justify-content:space-between;gap:12px;margin:26px 0 12px}.section-head h2{margin:0;font-size:20px}.section-head p{margin:3px 0 0;color:var(--muted);font-size:13px}.progress-wrap{width:100%;height:9px;background:var(--surface2);border-radius:999px;overflow:hidden}.progress-bar{height:100%;background:linear-gradient(90deg,#111,#d00,#ffce00);border-radius:999px}.lesson-card{padding:18px;cursor:pointer;transition:.18s}.lesson-card:hover{transform:translateY(-2px);border-color:#98a2b3}.lesson-top{display:flex;justify-content:space-between;gap:12px}.lesson-badge,.pill{display:inline-flex;align-items:center;gap:5px;font-size:11px;font-weight:800;padding:5px 8px;border-radius:999px;background:var(--surface2);color:var(--muted)}.lesson-card h3{margin:10px 0 7px;font-size:17px}.lesson-card p{margin:0;color:var(--muted);font-size:13px;line-height:1.55}.lesson-meta{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}.done-mark{color:var(--success);font-weight:900}.toolbar{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:16px}.field,.select{background:var(--surface);border:1px solid var(--line);color:var(--text);border-radius:12px;padding:11px 13px;outline:none}.field{min-width:220px;flex:1}.vocab-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.word-card{padding:17px;position:relative}.word-head{display:flex;justify-content:space-between;gap:8px}.word{font-size:21px;font-weight:900}.article{color:#d92d20;margin-right:5px}.meaning{margin:4px 0 10px;font-weight:700}.pron{color:var(--muted);font-size:13px}.example{margin-top:12px;padding-top:12px;border-top:1px dashed var(--line);line-height:1.55;font-size:13px}.example .de{font-weight:700}.example .bn{color:var(--muted);margin-top:3px}.mini-actions{display:flex;gap:6px}.mini-btn{border:1px solid var(--line);background:var(--surface2);color:var(--text);border-radius:9px;width:34px;height:34px;cursor:pointer}.grammar-card{padding:18px}.grammar-card h3{margin:8px 0}.grammar-card p{color:var(--muted);line-height:1.65}.grammar-example{background:var(--surface2);border-radius:12px;padding:12px;margin-top:10px}.grammar-example strong{display:block}.quiz-card{max-width:780px;margin:10px auto;padding:24px}.quiz-question{font-size:24px;font-weight:850;margin:12px 0 18px}.options{display:grid;gap:10px}.option{border:1px solid var(--line);background:var(--surface);color:var(--text);padding:13px 14px;border-radius:12px;text-align:left;cursor:pointer}.option:hover{border-color:#98a2b3}.option.correct{border-color:var(--success);background:color-mix(in srgb,var(--success) 12%,var(--surface))}.option.wrong{border-color:var(--danger);background:color-mix(in srgb,var(--danger) 10%,var(--surface))}.flashcard{max-width:720px;margin:10px auto;padding:30px;min-height:310px;display:grid;place-items:center;text-align:center}.flashcard .word{font-size:42px}.flashcard .meaning{font-size:24px}.flashcard .pron{font-size:17px}.flash-actions{display:flex;justify-content:center;gap:10px;margin-top:22px}.listening-box{max-width:820px;margin:auto;padding:24px}.listen-text{font-size:28px;font-weight:850;text-align:center;padding:28px}.answer-input{width:100%;margin-top:14px}.exam-banner{padding:20px;display:flex;justify-content:space-between;align-items:center;gap:16px}.timer{font-size:24px;font-weight:900}.plan-table{width:100%;border-collapse:collapse}.plan-table th,.plan-table td{padding:13px;border-bottom:1px solid var(--line);text-align:left}.plan-table th{font-size:12px;color:var(--muted);text-transform:uppercase}.settings-row{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:16px 0;border-bottom:1px solid var(--line)}.settings-card{padding:6px 20px}.empty{padding:36px;text-align:center;color:var(--muted)}.modal-backdrop[hidden]{display:none!important}.modal-backdrop{position:fixed;inset:0;background:rgba(0,0,0,.5);z-index:50;display:grid;place-items:center;padding:20px}.modal{background:var(--surface);color:var(--text);width:min(920px,100%);max-height:88vh;overflow:auto;border-radius:22px;box-shadow:0 30px 80px rgba(0,0,0,.35);padding:22px}.modal-head{display:flex;justify-content:space-between;gap:15px;align-items:start}.close-btn{border:0;background:var(--surface2);color:var(--text);width:36px;height:36px;border-radius:10px;cursor:pointer}.lesson-section{margin:22px 0}.lesson-section h3{margin-bottom:10px}.sentence-row{padding:12px;border:1px solid var(--line);border-radius:12px;margin:9px 0}.sentence-row .de{font-weight:800}.sentence-row .bn{color:var(--muted);margin-top:4px}.sentence-row .pron{margin-top:4px}.toast{position:fixed;right:20px;bottom:20px;background:#101828;color:#fff;padding:12px 16px;border-radius:12px;z-index:100;opacity:0;transform:translateY(15px);pointer-events:none;transition:.2s}.toast.show{opacity:1;transform:none}.level-card{padding:20px}.level-card h3{margin:0 0 6px}.level-card ul{padding-left:20px;color:var(--muted);line-height:1.8}.hero-flag{display:grid;place-items:center;position:relative}.flag{width:220px;max-width:100%;aspect-ratio:5/3;border-radius:18px;overflow:hidden;box-shadow:0 16px 40px rgba(0,0,0,.28)}.flag div{height:33.333%}.black{background:#111}.red{background:#d00}.gold{background:#ffce00}.notice{padding:13px 15px;border-radius:12px;background:color-mix(in srgb,var(--accent) 15%,var(--surface));border:1px solid color-mix(in srgb,var(--accent) 36%,var(--line));font-size:13px;line-height:1.6}.score-big{font-size:48px;font-weight:950}.kbd{font-family:ui-monospace,monospace;background:var(--surface2);padding:2px 6px;border-radius:6px;border:1px solid var(--line)}
@media(max-width:1100px){.vocab-grid{grid-template-columns:repeat(2,1fr)}.grid-3{grid-template-columns:repeat(2,1fr)}.stats{grid-template-columns:repeat(2,1fr)}}
@media(max-width:800px){.sidebar{transform:translateX(-105%);transition:.2s;box-shadow:20px 0 50px rgba(0,0,0,.35)}.sidebar.open{transform:none}.main{margin-left:0}.mobile-menu{display:block}.topbar{padding:14px 16px}.content{padding:18px 14px 84px}.hero{grid-template-columns:1fr;padding:22px}.hero h2{font-size:27px}.hero-flag{display:none}.grid-2,.grid-3,.vocab-grid{grid-template-columns:1fr}.stats{grid-template-columns:repeat(2,1fr)}.streak-pill{display:none}.toolbar .field,.toolbar .select{width:100%;min-width:0}.exam-banner{align-items:flex-start;flex-direction:column}.plan-table{font-size:12px}.modal{padding:18px}.flashcard .word{font-size:34px}}

/* B1GO brand polish */
.brand{min-height:68px}.brand-mark{display:flex;flex-direction:column;justify-content:center;gap:0;line-height:.82;background:#0b1220;border:1px solid rgba(255,255,255,.18);box-shadow:inset 0 0 0 2px rgba(255,255,255,.04)}.brand-mark span{font-size:18px;font-weight:950;letter-spacing:-.7px}.brand-mark small{font-size:8px;font-weight:900;letter-spacing:2px;color:#ffce00;margin-left:2px}.brand-copy{min-width:0}.brand-copy strong{font-size:21px;letter-spacing:.02em}.brand-copy span{font-size:10.5px;line-height:1.25;max-width:155px;color:#94a3b8}.hero h2{letter-spacing:-.025em}.hero h2::first-letter{color:#ffce00}.lesson-badge{letter-spacing:.035em}.topbar h1{letter-spacing:-.015em}
@media(max-width:720px){.brand-copy span{max-width:170px}.hero h2{font-size:27px}}
.brand-mark{align-items:center}.brand-mark span{color:#fff}.brand-mark small{display:block}