/* ==========================================================================
   ISO — Sistemas Operativos · app de estudio
   ========================================================================== */

:root{
  --bg:#f4f5f8;
  --bg-2:#eceef3;
  --panel:#ffffff;
  --panel-2:#fafbfd;
  --sunk:#f1f3f7;
  --ink:#0f141b;
  --ink-2:#333d4c;
  --muted:#5d6879;
  --faint:#8b95a6;
  --line:#e1e5ec;
  --line-2:#d3d9e3;
  --brand:#4f46e5;
  --brand-ink:#ffffff;
  --brand-soft:#eef0ff;
  --ok:#0f7b4f;
  --ok-soft:#e2f6ec;
  --bad:#b3261e;
  --bad-soft:#fde9e7;
  --warn:#a35b00;
  --warn-soft:#fdf0dc;
  --j1:#4f6fdb; --j2:#c9761b; --j3:#1e8f6a; --j4:#b23c85; --j5:#6b57d6;
  --shadow:0 1px 2px rgba(16,24,40,.05), 0 8px 24px -12px rgba(16,24,40,.12);
  --shadow-lg:0 2px 4px rgba(16,24,40,.04), 0 24px 48px -24px rgba(16,24,40,.22);
  --r:14px;
  --r-sm:9px;
  --f:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --fm:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,"Liberation Mono",monospace;
  --wrap:1180px;
  color-scheme:light;
}

@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){
    --bg:#0a0c10;
    --bg-2:#0d1015;
    --panel:#12161d;
    --panel-2:#151a22;
    --sunk:#0e1218;
    --ink:#e9edf4;
    --ink-2:#c3ccda;
    --muted:#94a0b2;
    --faint:#6d7889;
    --line:#222834;
    --line-2:#2c3441;
    --brand:#8b84ff;
    --brand-ink:#0b0d12;
    --brand-soft:#1b1c33;
    --ok:#4cd39a;
    --ok-soft:#12291f;
    --bad:#ff8b7f;
    --bad-soft:#2e1917;
    --warn:#f0b04e;
    --warn-soft:#2b2113;
    --j1:#7d97ff; --j2:#f2a34e; --j3:#46c797; --j4:#e57ab8; --j5:#a08cff;
    --shadow:0 1px 2px rgba(0,0,0,.4), 0 8px 24px -12px rgba(0,0,0,.6);
    --shadow-lg:0 2px 4px rgba(0,0,0,.4), 0 24px 48px -24px rgba(0,0,0,.8);
    color-scheme:dark;
  }
}
:root[data-theme="dark"]{
  --bg:#0a0c10; --bg-2:#0d1015; --panel:#12161d; --panel-2:#151a22; --sunk:#0e1218;
  --ink:#e9edf4; --ink-2:#c3ccda; --muted:#94a0b2; --faint:#6d7889;
  --line:#222834; --line-2:#2c3441;
  --brand:#8b84ff; --brand-ink:#0b0d12; --brand-soft:#1b1c33;
  --ok:#4cd39a; --ok-soft:#12291f; --bad:#ff8b7f; --bad-soft:#2e1917;
  --warn:#f0b04e; --warn-soft:#2b2113;
  --j1:#7d97ff; --j2:#f2a34e; --j3:#46c797; --j4:#e57ab8; --j5:#a08cff;
  --shadow:0 1px 2px rgba(0,0,0,.4), 0 8px 24px -12px rgba(0,0,0,.6);
  --shadow-lg:0 2px 4px rgba(0,0,0,.4), 0 24px 48px -24px rgba(0,0,0,.8);
  color-scheme:dark;
}

*,*::before,*::after{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font-family:var(--f);font-size:16px;line-height:1.62;
  -webkit-font-smoothing:antialiased;
  min-height:100vh;
  display:flex;flex-direction:column;
}
img{max-width:100%}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{line-height:1.2;margin:0;letter-spacing:-.018em;font-weight:700;text-wrap:balance}
h1{font-size:clamp(1.9rem,4vw,2.6rem)}
h2{font-size:clamp(1.35rem,2.4vw,1.7rem)}
h3{font-size:1.13rem;font-weight:650}
p{margin:0 0 .9em}
strong{font-weight:650;color:var(--ink)}
ul,ol{margin:0 0 .9em;padding-left:1.35em}
li{margin:.3em 0}
hr{border:0;border-top:1px solid var(--line);margin:1.6em 0}
code,.k{
  font-family:var(--fm);font-size:.88em;
  background:var(--sunk);border:1px solid var(--line);
  border-radius:5px;padding:.08em .38em;color:var(--ink-2);
  white-space:nowrap;
}
pre{
  font-family:var(--fm);font-size:.86rem;line-height:1.6;
  background:var(--sunk);border:1px solid var(--line);border-radius:var(--r-sm);
  padding:14px 16px;overflow-x:auto;margin:0 0 1em;
}
pre code{background:none;border:0;padding:0;white-space:pre}
::selection{background:var(--brand);color:var(--brand-ink)}
:focus-visible{outline:2px solid var(--brand);outline-offset:2px;border-radius:4px}

.wrap{max-width:var(--wrap);margin:0 auto;padding:0 22px;width:100%}
.mono{font-family:var(--fm)}
.muted{color:var(--muted)}
.small{font-size:.87rem}
.tiny{font-size:.78rem}

/* ---------- topbar ---------- */
.topbar{
  position:sticky;top:0;z-index:50;
  background:color-mix(in srgb,var(--bg) 86%,transparent);
  backdrop-filter:blur(14px) saturate(1.4);
  -webkit-backdrop-filter:blur(14px) saturate(1.4);
  border-bottom:1px solid var(--line);
}
.topbar-in{display:flex;align-items:center;gap:14px;height:60px}
.logo{display:flex;align-items:center;gap:10px;font-weight:750;letter-spacing:-.02em;font-size:1rem;color:var(--ink)}
.logo:hover{text-decoration:none}
.logo-mark{
  width:30px;height:30px;border-radius:9px;flex:0 0 auto;
  background:linear-gradient(145deg,var(--brand),#9333ea 70%);
  display:grid;place-items:center;color:#fff;font-family:var(--fm);
  font-size:.72rem;font-weight:700;letter-spacing:-.5px;
  box-shadow:0 2px 8px -2px color-mix(in srgb,var(--brand) 60%,transparent);
}
.logo small{display:block;font-weight:500;font-size:.68rem;color:var(--faint);letter-spacing:.04em;text-transform:uppercase;line-height:1}
.topnav{display:flex;gap:2px;margin-left:auto;align-items:center}
.topnav a{
  color:var(--muted);font-size:.9rem;font-weight:550;padding:7px 12px;border-radius:8px;
  white-space:nowrap;
}
.topnav a:hover{color:var(--ink);background:var(--sunk);text-decoration:none}
.topnav a.on{color:var(--ink);background:var(--panel);box-shadow:var(--shadow);border:1px solid var(--line)}
.icon-btn{
  width:34px;height:34px;display:grid;place-items:center;border-radius:8px;
  border:1px solid var(--line);background:var(--panel);color:var(--muted);cursor:pointer;
  font-size:.95rem;transition:.14s;
}
.icon-btn:hover{color:var(--ink);border-color:var(--line-2)}
@media (max-width:820px){
  .topnav a{padding:6px 8px;font-size:.82rem}
  .logo small{display:none}
}
@media (max-width:640px){
  .topbar-in{height:56px;gap:8px}
  .logo>span:last-child{display:none}
  .logo-mark{width:28px;height:28px}
  .topnav{gap:1px}
  .topnav a{padding:6px 8px;font-size:.79rem}
  .icon-btn{width:30px;height:30px;font-size:.85rem}
}
@media (max-width:400px){
  .topnav a{padding:6px 6px;font-size:.74rem}
  .wrap{padding:0 14px}
}

/* ---------- generic ---------- */
main{flex:1;padding:30px 0 80px}
.card{
  background:var(--panel);border:1px solid var(--line);border-radius:var(--r);
  padding:20px 22px;box-shadow:var(--shadow);
}
.grid{display:grid;gap:16px}
.g2{grid-template-columns:repeat(2,minmax(0,1fr))}
.g3{grid-template-columns:repeat(3,minmax(0,1fr))}
.g4{grid-template-columns:repeat(4,minmax(0,1fr))}
@media (max-width:900px){.g3,.g4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:640px){.g2,.g3,.g4{grid-template-columns:1fr}}

.tag{
  display:inline-flex;align-items:center;gap:5px;font-family:var(--fm);
  font-size:.7rem;letter-spacing:.05em;text-transform:uppercase;font-weight:600;
  padding:3px 8px;border-radius:999px;background:var(--sunk);color:var(--muted);
  border:1px solid var(--line);white-space:nowrap;
}
.tag.brand{background:var(--brand-soft);color:var(--brand);border-color:transparent}
.tag.ok{background:var(--ok-soft);color:var(--ok);border-color:transparent}
.tag.bad{background:var(--bad-soft);color:var(--bad);border-color:transparent}
.tag.warn{background:var(--warn-soft);color:var(--warn);border-color:transparent}

.btn{
  font:inherit;font-size:.92rem;font-weight:600;cursor:pointer;
  display:inline-flex;align-items:center;justify-content:center;gap:7px;
  padding:9px 16px;border-radius:9px;border:1px solid var(--line-2);
  background:var(--panel);color:var(--ink);transition:.14s;white-space:nowrap;
  text-decoration:none;
}
.btn:hover{border-color:var(--brand);color:var(--brand);text-decoration:none}
.btn:active{transform:translateY(1px)}
.btn.primary{background:var(--brand);border-color:var(--brand);color:var(--brand-ink)}
.btn.primary:hover{filter:brightness(1.08);color:var(--brand-ink)}
.btn.ghost{background:transparent;border-color:transparent;color:var(--muted);padding:7px 11px}
.btn.ghost:hover{background:var(--sunk);color:var(--ink);border-color:transparent}
.btn.sm{padding:6px 12px;font-size:.85rem}
.btn.lg{padding:12px 22px;font-size:1rem}
.btn:disabled{opacity:.4;cursor:not-allowed;transform:none}
.btn:disabled:hover{border-color:var(--line-2);color:var(--ink)}
.btn.primary:disabled:hover{color:var(--brand-ink)}

input[type=text],input[type=number],select,textarea{
  font:inherit;font-size:.95rem;color:var(--ink);
  background:var(--panel);border:1px solid var(--line-2);border-radius:8px;
  padding:8px 11px;width:100%;transition:.14s;
}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--brand);box-shadow:0 0 0 3px color-mix(in srgb,var(--brand) 18%,transparent)}
input.ans{font-family:var(--fm);letter-spacing:.02em}
input.ok,select.ok{border-color:var(--ok);background:var(--ok-soft)}
input.bad,select.bad{border-color:var(--bad);background:var(--bad-soft)}
select{cursor:pointer;appearance:none;background-image:linear-gradient(45deg,transparent 50%,var(--muted) 50%),linear-gradient(135deg,var(--muted) 50%,transparent 50%);background-position:calc(100% - 16px) 52%,calc(100% - 11px) 52%;background-size:5px 5px,5px 5px;background-repeat:no-repeat;padding-right:32px}

.row{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.spread{display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:space-between}
.hint{color:var(--muted);font-size:.86rem}
code.k{background:var(--sunk)}

/* ---------- hero / dashboard ---------- */
.hero{
  position:relative;overflow:hidden;
  border-radius:20px;padding:34px 34px 30px;
  background:
    radial-gradient(900px 400px at 88% -20%, color-mix(in srgb,var(--brand) 20%,transparent), transparent 62%),
    linear-gradient(180deg,var(--panel),var(--panel-2));
  border:1px solid var(--line);box-shadow:var(--shadow-lg);
}
.hero-grid{display:grid;grid-template-columns:1fr auto;gap:26px;align-items:center}
@media (max-width:820px){.hero{padding:26px 22px}.hero-grid{grid-template-columns:1fr;gap:20px}}
.hero h1{margin:10px 0 12px}
.hero p{color:var(--muted);max-width:52ch;margin:0 0 20px;font-size:1.02rem}
.hero-actions{display:flex;flex-wrap:wrap;gap:10px}
.eyebrow{
  font-family:var(--fm);font-size:.72rem;letter-spacing:.13em;text-transform:uppercase;
  color:var(--brand);font-weight:650;
}

.ring-wrap{display:flex;flex-direction:column;align-items:center;gap:8px}
.ring{position:relative;width:132px;height:132px}
.ring svg{transform:rotate(-90deg);display:block}
.ring-bg{stroke:var(--line);fill:none;stroke-width:9}
.ring-fg{stroke:url(#ringgrad);fill:none;stroke-width:9;stroke-linecap:round;transition:stroke-dashoffset .7s cubic-bezier(.4,0,.2,1)}
.ring-txt{position:absolute;inset:0;display:grid;place-items:center;text-align:center}
.ring-txt>div{display:flex;flex-direction:column;align-items:center;gap:2px}
.ring-txt b{display:block;font-size:1.75rem;line-height:1;letter-spacing:-.03em}
.ring-txt span{display:block;font-size:.62rem;color:var(--muted);text-transform:uppercase;letter-spacing:.09em;font-family:var(--fm)}

.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-top:18px}
@media (max-width:760px){.stats{grid-template-columns:repeat(2,1fr)}}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:13px 15px}
.stat b{display:block;font-size:1.3rem;letter-spacing:-.02em;line-height:1.2}
.stat span{font-size:.76rem;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;font-family:var(--fm)}

/* ---------- module cards ---------- */
.mod{
  display:flex;flex-direction:column;gap:12px;position:relative;overflow:hidden;
  background:var(--panel);border:1px solid var(--line);border-radius:var(--r);
  padding:18px 20px;transition:.16s;color:inherit;text-decoration:none;
}
.mod:hover{border-color:var(--mod,var(--brand));transform:translateY(-2px);box-shadow:var(--shadow-lg);text-decoration:none}
.mod::before{content:"";position:absolute;inset:0 auto 0 0;width:3px;background:var(--mod,var(--brand));opacity:.85}
.mod-h{display:flex;align-items:flex-start;justify-content:space-between;gap:10px}
.mod-h h3{font-size:1.05rem}
.mod-meta{display:flex;gap:8px;flex-wrap:wrap;align-items:center;font-size:.78rem;color:var(--faint);font-family:var(--fm)}
.mod-bar{height:5px;border-radius:999px;background:var(--sunk);overflow:hidden}
.mod-bar i{display:block;height:100%;background:var(--mod,var(--brand));border-radius:999px;transition:width .5s}
.mod ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:3px}
.mod li{font-size:.83rem;color:var(--muted);display:flex;gap:7px;align-items:baseline;margin:0}
.mod li .dot{width:5px;height:5px;border-radius:50%;background:var(--line-2);flex:0 0 auto;position:relative;top:-2px}
.mod li.done{color:var(--faint)}
.mod li.done .dot{background:var(--ok)}

/* ---------- learning map ---------- */
.map-head{display:flex;flex-wrap:wrap;gap:16px;justify-content:space-between;align-items:flex-end;margin-bottom:22px}
.module-block{
  border:1px solid var(--line);border-radius:var(--r);background:var(--panel);
  margin-bottom:14px;overflow:hidden;box-shadow:var(--shadow);
}
.module-head{
  display:flex;align-items:center;gap:14px;padding:16px 20px;cursor:pointer;
  background:linear-gradient(180deg,transparent,color-mix(in srgb,var(--mod) 5%,transparent));
  user-select:none;
}
.module-head:hover{background:color-mix(in srgb,var(--mod) 6%,transparent)}
.module-num{
  width:38px;height:38px;border-radius:11px;display:grid;place-items:center;flex:0 0 auto;
  background:color-mix(in srgb,var(--mod) 14%,transparent);color:var(--mod);
  font-family:var(--fm);font-weight:700;font-size:.9rem;
}
.module-head h3{flex:1;font-size:1.02rem}
.module-head .meta{font-size:.78rem;color:var(--faint);font-family:var(--fm);white-space:nowrap}
.chev{transition:transform .2s;color:var(--faint);font-size:.8rem}
.module-block.open .chev{transform:rotate(90deg)}
.module-body{display:none;border-top:1px solid var(--line)}
.module-block.open .module-body{display:block}
.topic-row{
  display:flex;align-items:center;gap:13px;padding:11px 20px;
  border-bottom:1px solid var(--line);color:inherit;text-decoration:none;transition:.12s;
}
.topic-row:last-child{border-bottom:0}
.topic-row:hover{background:var(--sunk);text-decoration:none}
.tick{
  width:22px;height:22px;border-radius:50%;border:1.5px solid var(--line-2);flex:0 0 auto;
  display:grid;place-items:center;font-size:.62rem;color:transparent;transition:.15s;
  font-family:var(--fm);font-weight:700;
}
.topic-row.done .tick{background:var(--ok);border-color:var(--ok);color:#fff}
.topic-row.current{background:color-mix(in srgb,var(--brand) 7%,transparent)}
.topic-row.current .tick{border-color:var(--brand);box-shadow:0 0 0 3px color-mix(in srgb,var(--brand) 18%,transparent)}
.topic-row .t-title{flex:1;font-size:.93rem;font-weight:520}
.topic-row.done .t-title{color:var(--muted)}
.topic-row .t-meta{font-size:.74rem;font-family:var(--fm);color:var(--faint);white-space:nowrap}
.topic-row .t-score{font-family:var(--fm);font-size:.74rem}

/* ---------- lesson layout ---------- */
.lesson-layout{display:grid;grid-template-columns:250px minmax(0,1fr);gap:34px;align-items:start}
@media (max-width:980px){.lesson-layout{grid-template-columns:1fr;gap:18px}}
.lesson-side{position:sticky;top:78px;max-height:calc(100vh - 100px);overflow-y:auto;padding-right:6px;scrollbar-width:thin}
.lesson-side h4{font-size:.72rem;text-transform:uppercase;letter-spacing:.1em;color:var(--faint);font-family:var(--fm);margin:0 0 9px;font-weight:600}
.lesson-side h4 .chev{display:none}
.side-topic{
  display:flex;gap:9px;align-items:flex-start;padding:6px 9px;border-radius:7px;
  font-size:.83rem;color:var(--muted);text-decoration:none;line-height:1.35;margin-bottom:1px;
}
.side-topic:hover{background:var(--sunk);color:var(--ink);text-decoration:none}
.side-topic.on{background:var(--brand-soft);color:var(--brand);font-weight:600}
.side-foot{margin-top:12px;padding-top:10px;border-top:1px solid var(--line)}
.side-back{display:none}
.side-topic .n{font-family:var(--fm);font-size:.72rem;color:var(--faint);flex:0 0 auto;min-width:1.3em;padding-top:1px}
.side-topic.on .n{color:var(--brand)}
.side-topic.done .n::after{content:"✓";color:var(--ok)}
.side-topic.done .n i{display:none}
@media (max-width:980px){
  .lesson-side{position:static;max-height:none;border:0;border-radius:0;padding:0;background:transparent;margin-bottom:10px}
  .lesson-side-list{display:none;margin-top:8px;border:1px solid var(--line);border-radius:var(--r);background:var(--panel);padding:8px}
  .lesson-side.open .lesson-side-list{display:block}
  .lesson-side h4 .chev{display:inline}
  .lesson-side h4{
    cursor:pointer;margin:0;display:flex;justify-content:space-between;align-items:center;gap:10px;
    font-size:.78rem;color:var(--muted);background:var(--panel);border:1px solid var(--line);
    border-radius:var(--r);padding:11px 14px;
  }
  .lesson-side h4:hover{border-color:var(--line-2);color:var(--ink)}
  .lesson-side.open h4 .chev{transform:rotate(90deg)}
  .lesson-side .side-foot{display:none}
  .lesson-side .side-back{
    display:block;margin-top:8px;font-size:.86rem;color:var(--muted);
    text-decoration:none;padding:0 2px;
  }
  .lesson-side .side-back:hover{color:var(--ink);text-decoration:none}
  .lesson-side.open .side-back{display:none}
}

.lesson-main{min-width:0}
.crumb{display:flex;gap:8px;align-items:center;font-size:.8rem;color:var(--faint);margin-bottom:12px;flex-wrap:wrap;font-family:var(--fm)}
.crumb a{color:var(--muted)}
.crumb .sep{opacity:.5}
.lesson-head{margin-bottom:20px;padding-bottom:18px;border-bottom:1px solid var(--line)}
.lesson-head h1{font-size:clamp(1.6rem,3.4vw,2.15rem);margin:8px 0 10px}
.lesson-head .sub{color:var(--muted);font-size:1rem;max-width:66ch}

.prose{font-size:1.015rem;color:var(--ink-2)}
.prose h2{font-size:1.35rem;color:var(--ink);margin:2em 0 .6em;padding-top:.3em;scroll-margin-top:80px}
.prose h3{font-size:1.08rem;color:var(--ink);margin:1.6em 0 .5em;scroll-margin-top:80px}
.prose h4{font-size:.95rem;color:var(--ink);margin:1.3em 0 .4em;font-weight:650}
.prose>*:first-child{margin-top:0}
.prose ul,.prose ol{padding-left:1.3em}
.prose li{margin:.35em 0}
.prose blockquote{
  margin:1.2em 0;padding:12px 18px;border-left:3px solid var(--brand);
  background:color-mix(in srgb,var(--brand) 5%,transparent);border-radius:0 8px 8px 0;color:var(--ink-2);
}
.prose blockquote p:last-child{margin-bottom:0}
.prose table{width:100%;border-collapse:collapse;font-size:.88rem;margin:1.1em 0}
.prose th,.prose td{border:1px solid var(--line);padding:7px 11px;text-align:left;vertical-align:top}
.prose th{background:var(--sunk);font-weight:650;font-size:.82rem;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}
.prose tbody tr:nth-child(even) td{background:color-mix(in srgb,var(--sunk) 45%,transparent)}
.prose .num,.num{font-family:var(--fm);font-variant-numeric:tabular-nums}

.callout{
  display:flex;gap:12px;padding:14px 16px;border-radius:11px;margin:1.3em 0;
  border:1px solid var(--line);background:var(--panel-2);font-size:.94rem;
}
.callout .ic{font-size:1rem;flex:0 0 auto;line-height:1.5}
.callout p:last-child{margin-bottom:0}
.callout.tip{border-color:color-mix(in srgb,var(--ok) 30%,var(--line));background:var(--ok-soft)}
.callout.warn{border-color:color-mix(in srgb,var(--warn) 30%,var(--line));background:var(--warn-soft)}
.callout.bad{border-color:color-mix(in srgb,var(--bad) 30%,var(--line));background:var(--bad-soft)}
.callout.key{border-color:color-mix(in srgb,var(--brand) 25%,var(--line));background:var(--brand-soft)}

.formula-box{
  display:grid;grid-template-columns:auto 1fr;gap:7px 16px;align-items:baseline;
  background:var(--sunk);border:1px solid var(--line);border-radius:11px;
  padding:15px 18px;margin:1.2em 0;font-size:.92rem;
}
.formula-box b{font-family:var(--fm);color:var(--brand);font-weight:600;white-space:nowrap;font-size:.9rem}

details.acc{border:1px solid var(--line);border-radius:10px;background:var(--panel-2);margin:1em 0;overflow:hidden}
details.acc>summary{
  cursor:pointer;padding:11px 15px;font-weight:600;font-size:.94rem;
  list-style:none;display:flex;align-items:center;gap:9px;
}
details.acc>summary::-webkit-details-marker{display:none}
details.acc>summary::before{content:"▸";color:var(--brand);transition:transform .18s;font-size:.8rem}
details.acc[open]>summary::before{transform:rotate(90deg)}
details.acc>summary:hover{background:var(--sunk)}
details.acc .body{padding:2px 15px 14px;border-top:1px solid var(--line);font-size:.95rem}

/* ---------- quiz ---------- */
.quiz-block{
  margin-top:34px;border:1px solid var(--line);border-radius:var(--r);overflow:hidden;background:var(--panel);
  box-shadow:var(--shadow);
}
.quiz-head{
  padding:18px 22px;border-bottom:1px solid var(--line);
  background:linear-gradient(180deg,color-mix(in srgb,var(--brand) 7%,transparent),transparent);
  display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between;align-items:center;
}
.quiz-head h3{margin:0}
.quiz-body{padding:6px 22px 20px}
.q{padding:18px 0;border-bottom:1px dashed var(--line)}
.q:last-of-type{border-bottom:0}
.q .stem{font-weight:600;font-size:.97rem;margin-bottom:11px;line-height:1.5}
.q .stem .qn{font-family:var(--fm);color:var(--brand);font-weight:600;margin-right:6px}
.opts{display:flex;flex-direction:column;gap:7px}
.opt{
  display:flex;gap:10px;align-items:flex-start;padding:9px 13px;border-radius:9px;
  border:1px solid var(--line);background:var(--panel-2);cursor:pointer;font-size:.93rem;
  transition:.12s;user-select:none;
}
.opt:hover{border-color:var(--line-2);background:var(--sunk)}
.opt input{margin:.32em 0 0;accent-color:var(--brand);flex:0 0 auto;width:15px;height:15px;cursor:pointer}
.opt .lbl{font-family:var(--fm);color:var(--faint);font-weight:600;flex:0 0 auto;font-size:.85rem}
.opt.right{border-color:var(--ok);background:var(--ok-soft)}
.opt.right .lbl{color:var(--ok)}
.opt.wrong{border-color:var(--bad);background:var(--bad-soft)}
.opt.wrong .lbl{color:var(--bad)}
.opt.missed{border-color:var(--ok);background:transparent;border-style:dashed}
.opt.missed .lbl{color:var(--ok)}
.opt .why{display:block;font-size:.84rem;color:var(--muted);margin-top:5px;line-height:1.45}
.opt.locked{cursor:default}
.q-foot{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-top:10px}
.verdict{font-size:.86rem;font-weight:600;font-family:var(--fm)}
.verdict.ok{color:var(--ok)}
.verdict.bad{color:var(--bad)}
.score-pill{
  font-family:var(--fm);font-size:.82rem;font-weight:600;padding:5px 11px;border-radius:999px;
  background:var(--sunk);color:var(--muted);border:1px solid var(--line);white-space:nowrap;
}
.score-pill.ok{background:var(--ok-soft);color:var(--ok);border-color:transparent}
.score-pill.bad{background:var(--bad-soft);color:var(--bad);border-color:transparent}

.quiz-result{
  margin:20px 22px 22px;padding:18px 20px;border-radius:12px;border:1px solid var(--line);
  background:var(--panel-2);
}
.quiz-result.pass{border-color:color-mix(in srgb,var(--ok) 35%,var(--line));background:var(--ok-soft)}
.quiz-result.fail{border-color:color-mix(in srgb,var(--bad) 30%,var(--line));background:var(--bad-soft)}
.quiz-result b{font-size:1.05rem}

/* next/prev */
.lesson-nav{display:flex;gap:12px;justify-content:space-between;margin-top:34px;flex-wrap:wrap}
.lesson-nav a{
  flex:1 1 240px;display:flex;flex-direction:column;gap:3px;padding:13px 17px;
  border:1px solid var(--line);border-radius:11px;background:var(--panel);color:inherit;
  text-decoration:none;transition:.14s;min-width:0;
}
.lesson-nav a:hover{border-color:var(--brand);text-decoration:none;transform:translateY(-1px)}
.lesson-nav a small{font-size:.72rem;color:var(--faint);font-family:var(--fm);text-transform:uppercase;letter-spacing:.08em}
.lesson-nav a span{font-weight:600;font-size:.93rem;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.lesson-nav a.next{text-align:right;align-items:flex-end}

/* ---------- labs ---------- */
.page-head{margin-bottom:24px}
.page-head h1{margin-bottom:8px}
.page-head p{color:var(--muted);max-width:70ch;margin:0}

.lab-nav{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:24px}
.lab-nav a{
  padding:8px 14px;border-radius:9px;border:1px solid var(--line);background:var(--panel);
  color:var(--muted);font-size:.88rem;font-weight:550;text-decoration:none;
}
.lab-nav a:hover{border-color:var(--line-2);color:var(--ink);text-decoration:none}
.lab-nav a.on{background:var(--brand);border-color:var(--brand);color:var(--brand-ink)}

.tool{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:20px 22px;box-shadow:var(--shadow);margin-bottom:18px}
.tool-head{display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;align-items:center;margin-bottom:14px}
.tool-head h3{margin:0}

.tbl-wrap{overflow-x:auto;margin:1em 0;-webkit-overflow-scrolling:touch;scrollbar-width:thin}
.tbl-wrap::-webkit-scrollbar{height:8px}
.tbl-wrap::-webkit-scrollbar-thumb{background:var(--line-2);border-radius:99px}
.tbl-wrap::-webkit-scrollbar-track{background:transparent}
table{border-collapse:collapse;width:100%;font-size:.9rem}
th,td{border:1px solid var(--line);padding:8px 11px;text-align:left;vertical-align:middle}
th{background:var(--sunk);font-weight:650;font-size:.78rem;text-transform:uppercase;letter-spacing:.04em;color:var(--muted);white-space:nowrap}
tbody tr:nth-child(even) td{background:color-mix(in srgb,var(--sunk) 40%,transparent)}
td.num,th.num{font-family:var(--fm);text-align:right;font-variant-numeric:tabular-nums}
table input{width:100%;min-width:0;padding:5px 8px;font-size:.88rem}
table input.arr,table input.cpu,table input.pri{width:5em;font-family:var(--fm)}
table select{width:100%;padding:5px 26px 5px 8px;font-size:.88rem}

.gantt-wrap{overflow-x:auto;padding:6px 0 10px;margin:1em 0}
.gantt{
  display:grid;gap:2px;font-family:var(--fm);font-size:.72rem;
  align-items:center;width:max-content;
}
.gantt .lbl{
  font-size:.72rem;color:var(--muted);padding-right:10px;text-align:right;
  font-family:var(--fm);white-space:nowrap;
}
.gantt .c{
  height:28px;border-radius:4px;display:grid;place-items:center;
  color:#fff;font-weight:600;font-size:.72rem;
}
.gantt .c.e{background:var(--sunk);color:var(--faint);border:1px dashed var(--line-2)}
.gantt .arr{color:var(--brand);font-size:.7rem;height:16px;text-align:center;white-space:nowrap;overflow:visible;font-weight:600}
.gantt .t{color:var(--faint);font-size:.68rem;text-align:center;height:16px}

/* ---------- exam ---------- */
.exam-shell{max-width:900px;margin:0 auto}
.exam-bar{
  position:sticky;top:60px;z-index:20;display:flex;flex-wrap:wrap;gap:12px;
  justify-content:space-between;align-items:center;padding:12px 18px;margin-bottom:22px;
  background:var(--panel);border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);
}
.timer{font-family:var(--fm);font-size:1.15rem;font-weight:700;letter-spacing:.02em;font-variant-numeric:tabular-nums}
.timer.low{color:var(--bad)}
.exam-sec{margin-bottom:26px}
.exam-sec>h3{display:flex;gap:9px;align-items:center;margin-bottom:12px}
.pts{font-family:var(--fm);font-size:.72rem;color:var(--brand);background:var(--brand-soft);padding:3px 8px;border-radius:999px;font-weight:600}
.memq{display:flex;flex-wrap:wrap;gap:10px;align-items:center;padding:7px 0}
.memq .lab{font-family:var(--fm);font-size:.88rem;font-weight:600;min-width:8.5em}
.memq input{width:9em}
.memq .steps{flex:1 1 100%;font-size:.82rem;color:var(--muted);font-family:var(--fm);line-height:1.5;padding-left:calc(8.5em + 10px)}
.memq.wide{display:grid;max-width:780px;grid-template-columns:minmax(0,1fr) 11em;gap:6px 16px;align-items:center;padding:8px 0;border-bottom:1px dashed var(--line)}
.memq.wide:last-child{border-bottom:0}
.memq.wide .qtext{font-size:.94rem;line-height:1.45}
.memq.wide .qtext b{font-family:var(--fm);color:var(--faint);margin-right:6px}
.memq.wide input{width:100%}
.memq.wide .steps{grid-column:1/-1;padding-left:0}
@media (max-width:620px){.memq.wide{grid-template-columns:1fr}}

.vf{display:flex;flex-wrap:wrap;gap:10px;align-items:flex-start;padding:11px 0;border-bottom:1px dashed var(--line)}
.vf:last-child{border-bottom:0}
.vf .txt{flex:1 1 300px;font-size:.93rem}
.vf .btns{display:flex;gap:6px;flex:0 0 auto}
.vf .btns button{font:600 .82rem var(--fm);padding:5px 12px;border-radius:7px;border:1px solid var(--line-2);background:var(--panel);cursor:pointer;color:var(--muted)}
.vf .btns button:hover{border-color:var(--brand);color:var(--brand)}
.vf .btns button.sel{background:var(--brand);border-color:var(--brand);color:var(--brand-ink)}
.vf.ok .btns button.sel{background:var(--ok);border-color:var(--ok)}
.vf.bad .btns button.sel{background:var(--bad);border-color:var(--bad)}
.vf .exp{flex:1 1 100%;font-size:.84rem;color:var(--muted)}

/* ---------- misc ---------- */
.toast{
  position:fixed;left:50%;bottom:26px;transform:translate(-50%,20px);
  background:var(--ink);color:var(--bg);padding:10px 18px;border-radius:999px;
  font-size:.88rem;font-weight:600;box-shadow:var(--shadow-lg);z-index:200;
  opacity:0;pointer-events:none;transition:.24s;max-width:90vw;
}
.toast.show{opacity:1;transform:translate(-50%,0)}
.empty{text-align:center;padding:50px 20px;color:var(--muted)}
.spinner{width:22px;height:22px;border:2px solid var(--line);border-top-color:var(--brand);border-radius:50%;animation:spin .7s linear infinite;margin:40px auto}
@keyframes spin{to{transform:rotate(360deg)}}
footer.site{border-top:1px solid var(--line);padding:24px 0;margin-top:40px;color:var(--faint);font-size:.82rem}
footer.site .wrap{display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between}

kbd{font-family:var(--fm);font-size:.8em;border:1px solid var(--line-2);border-bottom-width:2px;border-radius:5px;padding:1px 5px;background:var(--panel)}

.chip-row{display:flex;flex-wrap:wrap;gap:7px;margin:10px 0}
.chip{font-size:.8rem;padding:4px 10px;border-radius:999px;background:var(--sunk);border:1px solid var(--line);color:var(--muted);font-family:var(--fm)}

.progress-line{height:6px;background:var(--sunk);border-radius:999px;overflow:hidden;margin:8px 0}
.progress-line i{display:block;height:100%;background:var(--brand);border-radius:999px;transition:width .5s}

@media print{
  .topbar,footer.site,.lesson-side,.lesson-nav,.quiz-block,.lab-nav{display:none!important}
  body{background:#fff}
  .lesson-layout{grid-template-columns:1fr}
}

/* ---------- content widgets ---------- */
.lead{font-size:1.06rem;color:var(--ink-2)}
.walk{display:flex;flex-direction:column;gap:7px;max-width:82ch;margin:1em 0;padding:0;list-style:none}
.walk li{display:grid;grid-template-columns:4.2em 1fr;gap:10px;align-items:baseline;margin:0}
.walk li b{font-family:var(--fm);font-size:.78rem;color:var(--warn);font-weight:600;white-space:nowrap}
.demo{display:flex;flex-direction:column;gap:10px;margin:1.2em 0}
.formula{font-family:var(--fm);font-size:.84rem;display:grid;grid-template-columns:auto 1fr;gap:5px 14px;align-items:baseline}
.formula b{color:var(--brand);font-weight:600;white-space:nowrap}
.card.mini{padding:15px 17px;box-shadow:none;background:var(--sunk)}
.memmap{display:flex;flex-wrap:wrap;gap:20px;align-items:flex-start;margin:1.2em 0}
.memmap .col{display:flex;flex-direction:column;gap:3px;min-width:0}
.memmap .col h4{margin:0 0 5px;font:600 .72rem var(--fm);color:var(--faint);letter-spacing:.06em;text-transform:uppercase}
.memmap .blk{display:grid;grid-template-columns:auto 1fr;gap:10px;align-items:center;font:.78rem var(--fm);border:1px solid var(--line);border-radius:6px;padding:5px 10px;background:var(--sunk);min-width:210px}
.memmap .blk.on{color:#fff;border-color:transparent;font-weight:600}
.memmap .blk span:last-child{text-align:right}
.bits{display:flex;flex-wrap:wrap;gap:16px;align-items:flex-end;font-family:var(--fm);margin:1.2em 0}
.bits .grp{display:flex;flex-direction:column;gap:5px}
.bits .row2{display:flex;gap:2px}
.bits .b{width:23px;height:27px;display:flex;align-items:center;justify-content:center;border-radius:4px;font-weight:600;font-size:.78rem}
.bits .pg .b{background:var(--brand-soft);color:var(--brand)}
.bits .of .b{background:var(--warn-soft);color:var(--warn)}
.bits .cap{font-size:.76rem;color:var(--muted)}
.prose .tag{margin-right:2px}
table.mini{font-size:.86rem}
table.mini th,table.mini td{padding:6px 9px}

@media (max-width:980px){
  .lesson-side .lesson-side-list .side-topic{padding:8px 10px;font-size:.87rem}
}

/* tablas de carga de datos: en móvil se desplazan, no se aplastan */
@media (max-width:760px){
  #lotBody{white-space:nowrap}
  .tool .tbl-wrap>table{min-width:540px}
  .tool .tbl-wrap>table.res{min-width:470px;font-size:.78rem}
  .tool .tbl-wrap>table.res th,.tool .tbl-wrap>table.res td{padding:6px 7px;white-space:nowrap}
  .tool .tbl-wrap{-webkit-overflow-scrolling:touch}
  .tbl-wrap.scroll-hint{position:relative}
  .tool .tbl-wrap{padding-bottom:4px}
  .lab-nav{gap:6px}
  .lab-nav a{padding:7px 11px;font-size:.83rem}
  .exam-bar{top:56px}
  .gantt .lbl{font-size:.68rem;padding-right:7px}
  .page-head h1{font-size:1.7rem}
  .tool{padding:16px 15px}
  .quiz-head{padding:14px 15px}
  .quiz-body{padding:4px 15px 16px}
  .quiz-result{margin:16px 15px 18px}
  .prose{font-size:.99rem}
  .prose table{font-size:.82rem}
  .prose th,.prose td{padding:6px 8px}
}
@media (max-width:440px){
  .stats{grid-template-columns:repeat(2,1fr);gap:8px}
  .stat{padding:10px 12px}
  .stat b{font-size:1.15rem}
  .hero{padding:22px 18px}
  .hero h1{font-size:1.6rem}
  .lesson-nav a{flex:1 1 100%}
}

/* ---------- stepper de lección ---------- */
.stepper{border:1px solid var(--line);border-radius:var(--r);background:var(--panel);padding:16px 18px;margin:1.2em 0;box-shadow:var(--shadow)}
.stepper-head{display:flex;gap:10px;align-items:center;margin-bottom:8px;flex-wrap:wrap}
.stepper-ctl{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px;padding-top:12px;border-top:1px solid var(--line)}
@media (max-width:520px){
  .stepper{padding:13px 12px}
  .stepper-ctl .btn{flex:1 1 auto}
}