*{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#f1f5f9;--side:#ffffff;--card:#ffffff;--bd:#e2e8f0;
  --code:#1e293b;--acc:#f97316;--acc2:#3b82f6;
  --ok:#16a34a;--err:#dc2626;--warn:#d97706;
  --tx:#0f172a;--tx2:#475569;--tx3:#94a3b8;
  --kw:#7c3aed;--str:#16a34a;--num:#ea580c;--cmt:#94a3b8;--fn:#2563eb;--tp:#b45309;
}
body{font-family:'Segoe UI',system-ui,sans-serif;background:var(--bg);color:var(--tx);height:100vh;overflow:hidden}
#app{display:flex;height:100vh}

/* ── SIDEBAR ── */
#sidebar{width:270px;min-width:270px;background:var(--side);border-right:1px solid var(--bd);display:flex;flex-direction:column;overflow-y:auto;box-shadow:2px 0 8px rgba(0,0,0,.06)}
.sidebar-header{padding:20px 16px;border-bottom:1px solid var(--bd)}
.logo{display:flex;align-items:center;gap:10px;margin-bottom:16px}
.logo-icon{font-size:26px}
.logo-title{font-size:18px;font-weight:700;color:var(--acc)}
.logo-sub{font-size:11px;color:var(--tx3)}
.score-widget{background:var(--bg);border-radius:10px;padding:12px;border:1px solid var(--bd)}
.score-lbl{font-size:10px;text-transform:uppercase;letter-spacing:1px;color:var(--tx3);display:block;margin-bottom:4px}
.score-nums{font-size:20px;font-weight:700;color:var(--acc);display:block;margin-bottom:8px}
#block-nav{list-style:none;padding:10px 10px;flex:1}
.nav-btn{width:100%;padding:11px 12px;background:transparent;border:none;color:var(--tx2);text-align:left;cursor:pointer;border-radius:10px;display:flex;align-items:center;gap:10px;transition:all .2s;font-size:13px;margin-bottom:3px}
.nav-btn:hover{background:rgba(249,115,22,.08);color:var(--tx)}
.nav-btn.active{background:rgba(249,115,22,.12);color:var(--acc);font-weight:600}
.nav-tag{font-size:10px;font-weight:700;background:var(--bg);border:1px solid var(--bd);border-radius:5px;padding:2px 6px;min-width:38px;text-align:center;color:var(--tx3)}
.nav-btn.active .nav-tag{background:var(--acc);color:#fff;border-color:var(--acc)}
.nav-title{flex:1;font-size:12px;line-height:1.3}
.nav-pts{font-size:11px;font-weight:600;color:var(--tx3)}
.nav-btn.active .nav-pts{color:var(--acc)}

/* ── MAIN ── */
#main{flex:1;display:flex;flex-direction:column;overflow:hidden}
#block-header{padding:22px 32px 16px;border-bottom:1px solid var(--bd);background:#ffffff;box-shadow:0 1px 4px rgba(0,0,0,.06)}
.tag{display:inline-block;background:var(--acc);color:#fff;font-size:10px;font-weight:700;padding:3px 10px;border-radius:20px;margin-bottom:6px;letter-spacing:1px}
#header-title{font-size:22px;font-weight:700;margin-bottom:5px;color:var(--tx)}
#header-desc{font-size:13px;color:var(--tx2);margin-bottom:12px}

/* ── PROGRESS BARS ── */
.bar-bg{background:var(--bd);border-radius:4px;height:6px;overflow:hidden}
.bar-bg.thin{height:4px;max-width:400px}
.bar-fill{height:100%;background:var(--acc);border-radius:4px;transition:width .4s ease;width:0%}
.bar-fill.accent2{background:linear-gradient(90deg,var(--acc),var(--warn))}

/* ── TABS ── */
#tabs-bar{display:flex;gap:4px;padding:10px 32px;border-bottom:1px solid var(--bd);background:var(--side);overflow-x:auto}
.tab-btn{padding:7px 16px;border:none;background:transparent;color:var(--tx2);border-radius:8px;cursor:pointer;font-size:12px;font-weight:500;white-space:nowrap;transition:all .2s;font-family:inherit}
.tab-btn:hover{background:rgba(249,115,22,.08);color:var(--tx)}
.tab-btn.active{background:var(--acc);color:#fff;font-weight:600}

/* ── CONTENT AREA ── */
#content-area{flex:1;overflow-y:auto;padding:26px 32px}

/* ── THEORY ── */
.th-card{background:var(--card);border:1px solid var(--bd);border-radius:14px;padding:22px;margin-bottom:18px;box-shadow:0 1px 4px rgba(0,0,0,.04)}
.th-card h3{font-size:17px;color:var(--acc);margin-bottom:12px;display:flex;align-items:center;gap:8px}
.th-card p,.th-card li{font-size:13px;line-height:1.75;color:var(--tx2);margin-bottom:8px}
.th-card ul,.th-card ol{margin:8px 0 8px 20px}
.th-card table{width:100%;border-collapse:collapse;margin:10px 0;font-size:12px}
.th-card th{background:var(--bg);color:var(--acc);padding:8px 12px;text-align:left;border:1px solid var(--bd);font-weight:700}
.th-card td{padding:8px 12px;border:1px solid var(--bd);color:var(--tx2);vertical-align:top}
.th-card tr:nth-child(even) td{background:#f8fafc}
.th-card strong{color:var(--tx)}
.th-card .tag-info{background:rgba(59,130,246,.08);border:1px solid rgba(59,130,246,.2);color:var(--acc2);border-radius:8px;padding:10px 14px;font-size:13px;margin:10px 0}

/* ── CODE BLOCKS ── */
pre{background:var(--code);border:1px solid #334155;border-radius:10px;padding:16px 18px;font-family:'Consolas','Courier New',monospace;font-size:12.5px;line-height:1.65;overflow-x:auto;margin:10px 0;color:#e2e8f0;white-space:pre;box-shadow:inset 0 1px 3px rgba(0,0,0,.3)}
pre .kw{color:#c084fc;font-weight:600}
pre .str{color:#86efac}
pre .num{color:#fdba74}
pre .cmt{color:#64748b;font-style:italic}
pre .fn{color:#93c5fd}
pre .tp{color:#fcd34d}

/* ── EXERCISE CARDS ── */
.ex-list{display:flex;flex-direction:column;gap:18px}
.ex-card{background:var(--card);border:1.5px solid var(--bd);border-radius:14px;padding:22px;transition:border-color .2s;box-shadow:0 1px 4px rgba(0,0,0,.04)}
.ex-card.ok{border-color:var(--ok);background:#f0fdf4}
.ex-card.ng{border-color:var(--err);background:#fef2f2}
.ex-head{display:flex;align-items:flex-start;gap:10px;margin-bottom:14px}
.ex-num{background:var(--acc);color:#fff;width:26px;height:26px;border-radius:7px;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;flex-shrink:0;margin-top:1px}
.ex-q{font-size:14px;font-weight:600;color:var(--tx);line-height:1.45}

/* ── MC OPTIONS ── */
.mc-opts{display:flex;flex-direction:column;gap:7px;margin-top:12px}
.mc-opt{padding:11px 14px;background:#f8fafc;border:1.5px solid var(--bd);border-radius:9px;cursor:pointer;color:var(--tx2);font-size:13px;text-align:left;transition:all .2s;display:flex;align-items:center;gap:9px;font-family:inherit;width:100%}
.mc-opt:hover:not(:disabled){border-color:var(--acc);color:var(--tx);background:rgba(249,115,22,.05)}
.mc-opt.c-ok{border-color:var(--ok);background:#f0fdf4;color:var(--ok)}
.mc-opt.c-ng{border-color:var(--err);background:#fef2f2;color:var(--err)}
.mc-opt.reveal{border-color:var(--ok);background:#f0fdf4;color:var(--ok)}
.mc-opt:disabled{cursor:default}
.opt-ltr{width:22px;height:22px;border-radius:5px;background:var(--bd);display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:700;flex-shrink:0;color:var(--tx3)}
.mc-opt.c-ok .opt-ltr{background:var(--ok);color:#fff}
.mc-opt.c-ng .opt-ltr{background:var(--err);color:#fff}
.mc-opt.reveal .opt-ltr{background:var(--ok);color:#fff}

/* ── FEEDBACK ── */
.fb{margin-top:10px;padding:10px 14px;border-radius:9px;font-size:13px;display:none;line-height:1.5}
.fb.ok{background:#f0fdf4;border:1px solid var(--ok);color:var(--ok);display:block}
.fb.ng{background:#fef2f2;border:1px solid var(--err);color:var(--err);display:block}

/* ── FILL ── */
.fill-code{background:var(--code);border:1px solid #334155;border-radius:10px;padding:16px 18px;font-family:'Consolas',monospace;font-size:12.5px;line-height:2;white-space:pre-wrap;margin:12px 0;color:#e2e8f0;box-shadow:inset 0 1px 3px rgba(0,0,0,.3)}
.fill-inp{background:rgba(249,115,22,.2);color:#fff;border:2px solid var(--acc);border-radius:5px;padding:1px 6px;font-family:'Consolas',monospace;font-size:12px;min-width:60px;width:auto;text-align:center;outline:none;display:inline-block;transition:all .2s}
.fill-inp:focus{background:rgba(249,115,22,.35);box-shadow:0 0 0 2px rgba(249,115,22,.3)}
.fill-inp.ok{border-color:#86efac;background:rgba(134,239,172,.2);color:#86efac}
.fill-inp.ng{border-color:#fca5a5;background:rgba(252,165,165,.2);color:#fca5a5}
.btn{background:var(--acc);color:#fff;border:none;border-radius:9px;padding:9px 22px;cursor:pointer;font-size:13px;font-weight:600;transition:all .2s;font-family:inherit;margin-top:10px}
.btn:hover:not(:disabled){background:#ea580c;transform:translateY(-1px)}
.btn:disabled{opacity:.5;cursor:default;transform:none}
.btn.sec{background:transparent;border:1.5px solid var(--bd);color:var(--tx2);margin-left:8px}
.btn.sec:hover{border-color:var(--acc);color:var(--acc);transform:none}

/* ── ORDER ── */
.ord-wrap{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:14px}
.ord-built{min-height:180px;background:var(--code);border:2px dashed #475569;border-radius:10px;padding:12px;font-family:'Consolas',monospace;font-size:12px;transition:border-color .2s;color:#e2e8f0}
.ord-built.has{border-color:var(--acc)}
.ord-pool{display:flex;flex-direction:column;gap:6px}
.ord-line{padding:9px 13px;background:#f8fafc;border:1.5px solid var(--bd);border-radius:8px;cursor:pointer;font-family:'Consolas',monospace;font-size:12px;color:var(--tx);transition:all .2s;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;text-align:left;width:100%}
.ord-line:hover:not(.placed){border-color:var(--acc);background:rgba(249,115,22,.05)}
.ord-line.placed{opacity:.35;cursor:not-allowed}
.built-line{padding:5px 10px;border-radius:6px;background:rgba(249,115,22,.15);color:#e2e8f0;margin-bottom:3px;display:flex;justify-content:space-between;align-items:center;font-size:12px}
.rm-line{cursor:pointer;color:#fca5a5;margin-left:8px;font-size:15px;flex-shrink:0}
.rm-line:hover{opacity:.7}
.ord-labels{display:flex;gap:8px;margin-bottom:6px}
.ord-lbl{font-size:11px;font-weight:600;color:var(--tx3);text-transform:uppercase;letter-spacing:1px}

/* ── CHANGE ── */
.scenario-box{background:#f8fafc;border-left:3px solid var(--acc);border-radius:0 8px 8px 0;padding:12px 16px;margin-bottom:12px;font-size:13px;color:var(--tx2);line-height:1.6}
.change-q{font-size:13px;color:var(--warn);font-weight:600;margin:14px 0 10px;display:flex;align-items:center;gap:6px}

/* ── TOAST ── */
#toast{position:fixed;bottom:28px;right:28px;background:var(--card);border:1px solid var(--bd);border-radius:12px;padding:13px 20px;font-size:13px;z-index:999;transform:translateY(120px);opacity:0;transition:all .3s ease;pointer-events:none;max-width:300px;box-shadow:0 4px 16px rgba(0,0,0,.12)}
#toast.show{transform:translateY(0);opacity:1}
#toast.t-ok{border-color:var(--ok);background:#f0fdf4;color:var(--ok)}
#toast.t-ng{border-color:var(--err);background:#fef2f2;color:var(--err)}
#toast.t-inf{border-color:var(--acc2);color:var(--acc2)}

/* ── SECTION INTRO ── */
.sec-intro{margin-bottom:22px}
.sec-intro h2{font-size:20px;font-weight:700;margin-bottom:5px;display:flex;align-items:center;gap:8px;color:var(--tx)}
.sec-intro p{font-size:13px;color:var(--tx2)}

/* ── HINT ── */
.hint{background:rgba(217,119,6,.08);border:1px solid rgba(217,119,6,.2);border-radius:8px;padding:9px 13px;font-size:12px;color:var(--warn);margin-top:8px}

/* ── SCROLLBAR ── */
::-webkit-scrollbar{width:5px;height:5px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:var(--bd);border-radius:3px}
::-webkit-scrollbar-thumb:hover{background:var(--tx3)}

/* ── EXAM MODE ── */
.exam-toolbar{display:flex;flex-wrap:wrap;align-items:center;gap:14px;margin-bottom:18px;padding:14px 16px;background:var(--card);border:1px solid var(--bd);border-radius:12px;box-shadow:0 1px 4px rgba(0,0,0,.04)}
.exam-toolbar .btn{margin-top:0}
.exam-cats{display:flex;flex-wrap:wrap;align-items:center;gap:14px;font-size:12px;color:var(--tx2)}
.exam-catttl{font-weight:600;color:var(--tx3);text-transform:uppercase;letter-spacing:1px;font-size:10px}
.exam-catlbl{display:inline-flex;align-items:center;gap:5px;cursor:pointer;user-select:none}
.exam-catlbl input{accent-color:var(--acc);min-width:24px;min-height:24px}
.exam-card{background:var(--card);border:1.5px solid var(--bd);border-radius:12px;padding:16px 18px;cursor:pointer;transition:all .2s;box-shadow:0 1px 4px rgba(0,0,0,.04);margin-bottom:12px}
.exam-card:hover{border-color:var(--acc);transform:translateY(-1px);box-shadow:0 4px 10px rgba(249,115,22,.12)}
.exam-cardhd{display:flex;justify-content:space-between;align-items:center;margin-bottom:6px}
.exam-lbl{font-size:10px;font-weight:700;background:var(--bg);border:1px solid var(--bd);border-radius:5px;padding:2px 8px;color:var(--acc);letter-spacing:1px;text-transform:uppercase}
.exam-diff{color:var(--warn);font-size:13px;letter-spacing:1px}
.exam-tit{font-size:14px;font-weight:600;color:var(--tx);margin-bottom:8px;line-height:1.4}
.exam-meta{font-size:12px;color:var(--tx2);display:flex;gap:8px;flex-wrap:wrap}
.exam-last b{color:var(--acc)}
.exam-meta .muted{color:var(--tx3)}
.exam-actions{display:flex;gap:10px;align-items:center;margin-bottom:14px;flex-wrap:wrap}
.exam-actions .btn{margin-top:0}
.exam-prev{font-size:12px;color:var(--tx3);margin-left:auto}
.exam-prev b{color:var(--warn)}
.exam-steps{margin:8px 0 0 22px}
.exam-steps li{font-size:13px;line-height:1.7;color:var(--tx2);margin-bottom:4px}
.exam-codewrap{margin:14px 0}
.exam-code{line-height:2.05}
.exam-inp{background:rgba(249,115,22,.18);color:#fff;border:2px solid var(--acc);border-radius:5px;padding:1px 6px;font-family:'Consolas','Courier New',monospace;font-size:12px;min-width:44px;width:auto;text-align:center;outline:none;display:inline-block;transition:all .15s;vertical-align:baseline;margin:0 1px;text-transform:uppercase}
.exam-inp:focus{background:rgba(249,115,22,.32);box-shadow:0 0 0 2px rgba(249,115,22,.35)}
.exam-inp.ok{border-color:#86efac;background:rgba(134,239,172,.22);color:#86efac}
.exam-inp.ng{border-color:#fca5a5;background:rgba(252,165,165,.22);color:#fca5a5}
.exam-inp:disabled{cursor:default}
.exam-banner{display:inline-block;font-size:34px;font-weight:800;padding:10px 26px;border-radius:14px;letter-spacing:1px;margin:8px 0 14px;border:2px solid;background:#fff}
.exam-banner.ok{color:var(--ok);border-color:var(--ok);background:#f0fdf4}
.exam-banner.warn{color:var(--warn);border-color:var(--warn);background:#fffbeb}
.exam-banner.ng{color:var(--err);border-color:var(--err);background:#fef2f2}
.exam-errs{margin:8px 0 0 22px;font-size:12.5px}
.exam-errs li{margin-bottom:4px}
.exam-errs code{background:rgba(220,38,38,.08);padding:1px 6px;border-radius:4px;font-family:'Consolas',monospace}

/* ── PROBLEMAS RESUELTOS ── */
.prob-enun{background:#f8fafc;border-left:3px solid var(--acc2);border-radius:0 8px 8px 0;padding:12px 16px;margin-bottom:12px;font-size:13px;color:var(--tx2);line-height:1.7}
.prob-enun p{margin-bottom:6px}
.sched{display:block;background:var(--code);color:#e2e8f0;border-radius:8px;padding:10px 13px;font-family:'Consolas','Courier New',monospace;font-size:12px;margin:8px 0;white-space:pre-wrap;word-break:break-word;line-height:1.8}
.prob-sol{border:1px solid var(--bd);border-radius:10px;background:#fff;margin-top:4px}
.prob-sol[open]{box-shadow:0 1px 5px rgba(0,0,0,.06)}
.prob-sol>summary{cursor:pointer;padding:11px 16px;font-size:13px;font-weight:600;color:var(--acc);list-style:none;user-select:none;display:flex;align-items:center;gap:8px}
.prob-sol>summary::-webkit-details-marker{display:none}
.prob-sol>summary::before{content:'▶';font-size:9px;transition:transform .2s}
.prob-sol[open]>summary::before{transform:rotate(90deg)}
.prob-sol>summary:hover{background:rgba(249,115,22,.05);border-radius:10px}
.prob-sol-body{padding:4px 18px 18px;font-size:13px;color:var(--tx2);line-height:1.7}
.prob-sol-body h4{font-size:14px;color:var(--tx);margin:18px 0 8px;padding-bottom:5px;border-bottom:1px solid var(--bd)}
.prob-sol-body h4:first-child{margin-top:4px}
.prob-sol-body p{margin-bottom:7px}
.prob-sol-body ul,.prob-sol-body ol{margin:6px 0 10px 22px}
.prob-sol-body li{margin-bottom:5px;line-height:1.7}
.prob-sol-body table{width:100%;border-collapse:collapse;margin:10px 0;font-size:12px}
.prob-sol-body th{background:var(--bg);color:var(--acc);padding:6px 10px;border:1px solid var(--bd);text-align:left;font-weight:700}
.prob-sol-body td{padding:6px 10px;border:1px solid var(--bd);color:var(--tx2)}
.prob-sol-body code{background:rgba(124,58,237,.1);padding:1px 6px;border-radius:4px;font-family:'Consolas',monospace;font-size:12px;color:var(--kw)}
.prob-sol-body sup{font-size:9px;color:var(--tx3)}
.gph{background:#f8fafc;border:1px dashed var(--acc2);border-radius:8px;padding:11px 14px;margin:10px 0;font-family:'Consolas',monospace;font-size:12.5px;color:var(--tx);line-height:1.9}
.gph b{color:var(--acc2)}
.verdict{border-radius:8px;padding:10px 14px;margin:10px 0;font-size:13px;font-weight:600;line-height:1.5}
.verdict.yes{background:#f0fdf4;border:1px solid var(--ok);color:var(--ok)}
.verdict.no{background:#fef2f2;border:1px solid var(--err);color:var(--err)}
.prob-card .exam-lbl{margin-right:2px}

/* ── RESPONSIVE ── */
@media(max-width:900px){
  #sidebar{width:220px;min-width:220px}
  #content-area,#block-header,#tabs-bar{padding-left:16px;padding-right:16px}
}
@media(max-width:650px){
  #app{flex-direction:column}
  #sidebar{width:100%;min-width:100%;height:auto;max-height:180px}
  .ord-wrap{grid-template-columns:1fr}
  .exam-toolbar{flex-direction:column;align-items:stretch}
  .exam-banner{font-size:26px;padding:8px 18px}
}