:root{--bg:#f4f7fb;--panel:#fff;--ink:#172033;--muted:#64748b;--line:#dbe3ef;--brand:#2563eb;--brand2:#1d4ed8;--ok:#15803d;--bad:#b91c1c;--warn:#b45309;--code:#0f172a;--soft:#eff6ff}
*{box-sizing:border-box}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,sans-serif;background:var(--bg);color:var(--ink)}button,select,textarea{font:inherit}button{cursor:pointer}.app{min-height:100vh;display:grid;grid-template-columns:280px 1fr}.sidebar{background:#0f172a;color:#e2e8f0;padding:22px 16px;position:sticky;top:0;height:100vh;overflow:auto}.logo{font-size:23px;font-weight:850;letter-spacing:-.5px}.tagline{font-size:12px;color:#94a3b8;margin:4px 0 22px}.module{padding:12px;border-radius:10px;margin:6px 0;border:1px solid transparent}.module.active{background:#1e293b;border-color:#334155}.module.locked{opacity:.52}.module small{display:block;color:#94a3b8;margin-top:4px}.main{padding:20px;min-width:0}.topbar{display:flex;justify-content:space-between;gap:16px;align-items:center;margin-bottom:16px}.topbar h1{margin:0;font-size:24px}.dialects{display:flex;align-items:center;gap:8px}.dialects select{padding:9px 12px;border:1px solid var(--line);border-radius:9px;background:#fff}.stats{display:grid;grid-template-columns:repeat(4,minmax(120px,1fr));gap:10px;margin-bottom:14px}.stat{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:12px}.stat b{display:block;font-size:21px}.stat span{font-size:12px;color:var(--muted)}.progress{height:8px;background:#e2e8f0;border-radius:99px;overflow:hidden;margin-top:8px}.progress i{display:block;height:100%;background:var(--brand);width:0}.tabs{display:flex;gap:6px;margin-bottom:12px;flex-wrap:wrap}.tab{border:1px solid var(--line);background:#fff;padding:9px 13px;border-radius:9px}.tab.active{background:var(--brand);color:#fff;border-color:var(--brand)}.panel{display:none}.panel.active{display:block}.workspace{display:grid;grid-template-columns:minmax(300px,38%) 1fr;gap:14px}.card{background:var(--panel);border:1px solid var(--line);border-radius:14px;box-shadow:0 3px 14px rgba(15,23,42,.04)}.qcard{padding:18px}.eyebrow{font-size:12px;font-weight:800;color:var(--brand);text-transform:uppercase}.qtitle{font-size:21px;font-weight:800;line-height:1.35;margin:8px 0 12px}.signal{background:#dbeafe;border-radius:5px;padding:1px 4px;color:#1d4ed8;font-weight:700}.mapping{display:flex;gap:6px;flex-wrap:wrap;margin:10px 0}.pill{font-size:12px;background:var(--soft);color:#1e40af;padding:5px 8px;border-radius:999px}.framework summary,.hints summary{font-weight:750;cursor:pointer;margin:10px 0}.framework label{display:block;font-size:12px;color:var(--muted);margin:9px 0 4px}.framework input{width:100%;padding:8px;border:1px solid var(--line);border-radius:8px}.hintbox{padding:10px;background:#fffbeb;border:1px solid #fde68a;border-radius:9px;margin-top:8px}.hint-actions{display:flex;gap:6px;flex-wrap:wrap}.btn{border:0;border-radius:9px;padding:9px 12px;font-weight:750}.primary{background:var(--brand);color:#fff}.primary:hover{background:var(--brand2)}.secondary{background:#e2e8f0;color:#172033}.danger{background:#fee2e2;color:#991b1b}.editor-card{overflow:hidden}.editorbar{display:flex;align-items:center;justify-content:space-between;padding:10px 12px;border-bottom:1px solid #293548;background:#111827;color:#cbd5e1}.editorbar small{color:#94a3b8}.editor{width:100%;height:290px;resize:vertical;border:0;outline:0;background:var(--code);color:#e2e8f0;padding:16px;font:14px/1.6 ui-monospace,SFMono-Regular,Menlo,monospace;tab-size:2}.actions{display:flex;gap:8px;padding:10px 12px;background:#111827;border-top:1px solid #293548}.result{margin-top:14px;padding:14px}.status{font-weight:850;font-size:18px;margin-bottom:8px}.status.ok{color:var(--ok)}.status.bad{color:var(--bad)}.status.warn{color:var(--warn)}.tablewrap{overflow:auto;max-height:310px;border:1px solid var(--line);border-radius:9px}table{border-collapse:collapse;width:100%;font-size:13px}th,td{padding:9px 10px;border-bottom:1px solid var(--line);text-align:left;white-space:nowrap}th{background:#f8fafc;position:sticky;top:0}.feedback{margin-top:10px;background:#f0fdf4;border:1px solid #bbf7d0;padding:11px;border-radius:9px;white-space:pre-line}.navrow{display:flex;justify-content:space-between;gap:8px;margin-top:14px}.solution{margin-top:12px;padding:12px;border-radius:9px;background:#f8fafc;border:1px solid var(--line)}pre{white-space:pre-wrap;word-break:break-word;background:#0f172a;color:#e2e8f0;padding:12px;border-radius:9px}.question-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:10px}.qitem{padding:12px;background:#fff;border:1px solid var(--line);border-radius:10px;cursor:pointer}.qitem.done{border-left:5px solid var(--ok)}.qitem.current{outline:2px solid var(--brand)}.difficulty{font-size:11px;color:var(--muted)}.explorer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:12px}.schema-card{padding:14px}.rel{padding:14px;margin-bottom:12px;background:#eff6ff;border:1px solid #bfdbfe;border-radius:12px}.sample{overflow:auto}.history-item{padding:12px;border-bottom:1px solid var(--line)}.empty{padding:22px;color:var(--muted);text-align:center}.footer-note{font-size:12px;color:var(--muted);margin-top:14px}.mobile-menu{display:none}
@media(max-width:950px){.app{grid-template-columns:1fr}.sidebar{position:static;height:auto}.sidebar .module-list{display:none}.sidebar.open .module-list{display:block}.mobile-menu{display:inline-block}.workspace{grid-template-columns:1fr}.stats{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.main{padding:12px}.topbar{align-items:flex-start;flex-direction:column}.stats{grid-template-columns:1fr 1fr}.qtitle{font-size:18px}.actions{flex-wrap:wrap}}

/* SQL Mastery v1.0 landing page */
.landing{min-height:100vh;background:linear-gradient(145deg,#eef4ff 0%,#f8fafc 45%,#eefbf5 100%);display:flex;align-items:center;justify-content:center;padding:32px 20px}
.landing-shell{width:min(1080px,100%);background:rgba(255,255,255,.94);border:1px solid rgba(203,213,225,.9);border-radius:28px;box-shadow:0 30px 80px rgba(15,23,42,.13);overflow:hidden}
.landing-nav{display:flex;align-items:center;justify-content:space-between;padding:22px 30px;border-bottom:1px solid var(--line)}
.brand-lockup{display:flex;align-items:center;gap:12px}.brand-mark{width:44px;height:44px;border-radius:13px;background:#0f172a;color:#fff;display:grid;place-items:center;font-weight:900;letter-spacing:-1px}.brand-name{font-size:20px;font-weight:850}.version-chip{font-size:12px;font-weight:750;color:#1d4ed8;background:#dbeafe;border-radius:999px;padding:6px 10px}
.landing-hero{padding:72px 54px 38px;text-align:center}.eyebrow{display:inline-flex;align-items:center;gap:8px;background:#eff6ff;color:#1d4ed8;border:1px solid #bfdbfe;border-radius:999px;padding:7px 12px;font-size:13px;font-weight:750}.landing h1{font-size:clamp(42px,7vw,76px);letter-spacing:-3px;line-height:.98;margin:22px auto 18px;max-width:800px}.landing-lead{font-size:clamp(17px,2.5vw,21px);line-height:1.65;color:#475569;max-width:720px;margin:0 auto 28px}.start-btn{border:0;border-radius:13px;background:#2563eb;color:#fff;font-weight:800;padding:15px 24px;box-shadow:0 12px 24px rgba(37,99,235,.25)}.start-btn:hover{background:#1d4ed8;transform:translateY(-1px)}
.landing-facts{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;padding:24px 54px 54px}.landing-fact{border:1px solid var(--line);background:#fff;border-radius:18px;padding:22px;text-align:left}.landing-fact b{display:block;font-size:18px;margin-bottom:7px}.landing-fact span{color:#64748b;line-height:1.5;font-size:14px}.landing-footer{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:20px 30px;background:#0f172a;color:#cbd5e1;font-size:13px}.landing-footer strong{color:#fff}.landing-footer a{color:#bfdbfe;text-decoration:none}
.app{display:none}.app.is-visible{display:grid}.home-link{width:100%;margin-top:14px;background:transparent;color:#bfdbfe;border:1px solid #334155;border-radius:10px;padding:9px 12px;text-align:left}.product-footer{margin-top:28px;padding:18px 4px 4px;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:12px;color:#64748b;font-size:12px}.product-footer strong{color:#334155}.product-footer a{color:#2563eb;text-decoration:none}
@media(max-width:760px){.landing-hero{padding:52px 24px 28px}.landing-facts{grid-template-columns:1fr;padding:18px 24px 36px}.landing-nav,.landing-footer{padding:18px 20px}.landing-footer,.product-footer{align-items:flex-start;flex-direction:column}.landing h1{letter-spacing:-2px}.app.is-visible{display:block}}
.loading-overlay{position:fixed;inset:0;background:rgba(15,23,42,.72);color:#fff;display:grid;place-items:center;z-index:9999;font-weight:800}
.loading-overlay[hidden]{display:none}.error-box{padding:14px;border:1px solid #fecaca;background:#fef2f2;color:#991b1b;border-radius:10px}
.qitem b{display:block;margin-bottom:4px}.schema-card h3{margin:0 0 10px}.schema-card ul{margin:0;padding-left:18px;color:var(--muted)}


/* Grouped All Questions syllabus */
.question-list{display:block}
.question-group{margin-bottom:18px}
.question-group-heading{display:flex;align-items:center;justify-content:space-between;padding:10px 4px 8px;border-bottom:2px solid var(--line);text-transform:uppercase;letter-spacing:.08em;font-weight:850;color:var(--ink)}
.question-group-heading small{font-size:11px;color:var(--muted);font-weight:700;letter-spacing:0;text-transform:none}
.question-group-list{background:#fff;border:1px solid var(--line);border-top:0;border-radius:0 0 12px 12px;overflow:hidden}
.question-row{width:100%;display:grid;grid-template-columns:42px minmax(0,1fr) auto;align-items:center;gap:12px;padding:13px 14px;border:0;border-bottom:1px solid var(--line);background:#fff;text-align:left;color:var(--ink);transition:background .15s ease,box-shadow .15s ease}
.question-row:last-child{border-bottom:0}
.question-row:hover{background:#f8fafc}
.question-row.current{background:#eff6ff;box-shadow:inset 4px 0 0 var(--brand)}
.question-row.done{background:#fbfefc}
.question-number{width:32px;height:32px;display:grid;place-items:center;border-radius:50%;background:#f1f5f9;color:#475569;font-size:12px;font-weight:850}
.question-row.done .question-number{background:#dcfce7;color:#166534}
.question-copy{min-width:0}
.question-copy b{display:block;font-size:14px;line-height:1.35;margin:0 0 3px}
.question-copy small{font-size:11px;color:var(--muted)}
.question-status{display:inline-flex;align-items:center;gap:6px;white-space:nowrap;padding:6px 9px;border-radius:999px;font-size:11px;font-weight:800;border:1px solid transparent}
.question-status i{font-style:normal;font-weight:900}
.question-status.completed{background:#dcfce7;color:#166534;border-color:#bbf7d0}
.question-status.attempted{background:#fef3c7;color:#92400e;border-color:#fde68a}
.question-status.needs-work{background:#fee2e2;color:#991b1b;border-color:#fecaca}
.question-status.not-started{background:#f1f5f9;color:#64748b;border-color:#e2e8f0}
@media(max-width:640px){.question-row{grid-template-columns:34px minmax(0,1fr);gap:9px}.question-status{grid-column:2;justify-self:start}.question-number{width:28px;height:28px}.question-group-heading small{display:none}}

/* Dynamic platform home */
.home-landing{display:block;min-height:100vh;padding:28px}
.home-hero{padding-bottom:20px}
.home-module-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px;padding:10px 28px 40px}
.home-module-card{display:flex;flex-direction:column;min-height:260px;padding:22px;background:#fff;border:1px solid var(--line);border-radius:16px;text-decoration:none;color:var(--ink);box-shadow:0 5px 18px rgba(15,23,42,.05);transition:transform .18s ease,box-shadow .18s ease,border-color .18s ease}
.home-module-card:hover{transform:translateY(-3px);box-shadow:0 12px 30px rgba(15,23,42,.09);border-color:#93c5fd}
.home-module-number{font-size:12px;font-weight:850;text-transform:uppercase;letter-spacing:.08em;color:var(--brand)}
.home-module-card h2{margin:9px 0 8px;font-size:23px;text-transform:lowercase}
.home-module-card p{margin:0 0 20px;color:var(--muted);line-height:1.55;flex:1}
.home-module-meta{display:flex;justify-content:space-between;gap:10px;font-size:12px;color:var(--muted)}
.home-progress{height:7px;background:#e2e8f0;border-radius:99px;overflow:hidden;margin:10px 0 15px}
.home-progress i{display:block;height:100%;background:var(--brand)}
.module-list .module{display:block;color:inherit;text-decoration:none}
@media(max-width:640px){.home-landing{padding:0}.home-module-grid{padding:10px 16px 28px}.home-module-meta{align-items:flex-start;flex-direction:column}}