/* ══════════════════════════════════════════════════════════
   운영체제 첫걸음 — 노트북 스타일
   ══════════════════════════════════════════════════════════ */
:root{
  --blue:#3b82f6; --blue-s:#dbeafe; --mint:#10b981; --mint-s:#d1fae5;
  --coral:#f97316; --coral-s:#ffedd5; --violet:#8b5cf6; --violet-s:#ede9fe;
  --rose:#ef4444;  --rose-s:#fee2e2; --amber:#f59e0b; --amber-s:#fef3c7;
  --paper:#fff; --page:#f4f6fa; --ink:#1e293b; --ink-2:#475569; --ink-3:#94a3b8;
  --line:#e2e8f0; --line-2:#cbd5e1;
  --code-bg:#0f172a; --code-ink:#e2e8f0;
  --shadow:0 1px 3px rgba(15,23,42,.06),0 8px 24px -8px rgba(15,23,42,.10);
  --radius:16px;
}
[data-bs-theme="dark"]{
  --blue-s:#1e3a5f; --mint-s:#064e3b; --coral-s:#4a2610; --violet-s:#2e1065;
  --rose-s:#4c1d1d; --amber-s:#453005;
  --paper:#151b26; --page:#0b0f16; --ink:#e5e9f0; --ink-2:#a8b3c4; --ink-3:#6b7688;
  --line:#28303d; --line-2:#3a4453; --code-bg:#0a0e15;
  --shadow:0 1px 3px rgba(0,0,0,.4),0 8px 24px -8px rgba(0,0,0,.5);
}
*{ -webkit-tap-highlight-color:transparent }
html{ font-size:18px } /* --drson-root-font */
body{
  font-family:'Pretendard Variable',Pretendard,-apple-system,BlinkMacSystemFont,
              'Apple SD Gothic Neo','Malgun Gothic',system-ui,sans-serif;
  background:var(--page); color:var(--ink);
  font-size:1rem; line-height:1.78; letter-spacing:-.011em;
  word-break:keep-all; overflow-wrap:anywhere;
}
code,pre,.code-area,.mono{
  font-family:'JetBrains Mono','SF Mono',Menlo,Consolas,'D2Coding',monospace;
}

/* ── 상단바 ───────────────────────────────── */
.nb-top{
  background:color-mix(in srgb,var(--paper) 88%,transparent);
  backdrop-filter:blur(12px); border-bottom:1px solid var(--line); min-height:56px;
}
.nb-brand{ font-weight:800; font-size:1.05rem; color:var(--ink)!important; letter-spacing:-.02em }
.nb-brand span{ background:linear-gradient(90deg,var(--blue),var(--violet));
  -webkit-background-clip:text; background-clip:text; color:transparent }
.nb-progress{ align-items:center; gap:.5rem }
.nb-progress-bar{ width:110px; height:7px; background:var(--line); border-radius:99px; overflow:hidden }
.nb-progress-bar span{ display:block; height:100%; width:0;
  background:linear-gradient(90deg,var(--blue),var(--mint)); border-radius:99px; transition:width .45s ease }
#progText{ color:var(--ink-3); font-variant-numeric:tabular-nums; font-size:.78rem; white-space:nowrap }

/* ── 레이아웃 ─────────────────────────────── */
.nb-shell{ display:flex; align-items:flex-start; max-width:1500px; margin:0 auto; gap:0 }
.nb-main{ flex:1; min-width:0; padding:1.6rem clamp(.65rem,2.4vw,2rem) 4rem }

/* ── 목차 ────────────────────────────────── */
.nb-toc{ width:308px; flex:0 0 308px; background:var(--paper); border-right:1px solid var(--line) }
@media (min-width:992px){
  .nb-toc{ position:sticky; top:56px; height:calc(100vh - 56px); overflow-y:auto }
  .nb-toc::-webkit-scrollbar{ width:7px }
  .nb-toc::-webkit-scrollbar-thumb{ background:var(--line-2); border-radius:9px }
}
/* Bootstrap 은 ≥lg 에서 .offcanvas-body 를 display:flex(가로) + padding:0 으로 바꾼다.
   세로 목차이므로 되돌린다. */
.nb-toc .offcanvas-body{ display:block!important; padding:1rem .7rem!important; overflow-y:visible }
.toc-title{ font-size:.75rem; font-weight:800; color:var(--ink-3);
  letter-spacing:0; padding:.2rem .6rem .6rem }
.toc-list{ list-style:none; margin:0; padding:0; counter-reset:none }
.toc-item{
  display:flex; align-items:flex-start; gap:.6rem; padding:.5rem .6rem; margin-bottom:2px;
  border-radius:11px; text-decoration:none; color:var(--ink-2); transition:background .15s,color .15s;
}
.toc-item:hover{ background:var(--page); color:var(--ink) }
.toc-item.active{ background:var(--blue-s); color:var(--ink) }
.toc-item.active .toc-no{ background:var(--blue); color:#fff }
.toc-no{ flex:0 0 24px; height:24px; border-radius:8px; background:var(--line);
  color:var(--ink-2); font-size:.72rem; font-weight:800; display:grid; place-items:center; margin-top:3px }
.toc-body{ flex:1; min-width:0; line-height:1.42 }
.toc-name{ display:block; font-weight:700; font-size:.895rem }
.toc-sub{ display:block; font-size:.735rem; color:var(--ink-3); margin-top:1px }
.toc-check{ opacity:0; color:var(--mint); font-weight:900; margin-top:3px; transition:opacity .2s }
.toc-item.done .toc-check{ opacity:1 }
.toc-item.done .toc-no{ background:var(--mint-s); color:var(--mint) }
.toc-foot{ padding:1rem .6rem 2rem }

/* ── 종이 ────────────────────────────────── */
.nb-paper{
  background:var(--paper); border:1px solid var(--line); border-radius:var(--radius);
  box-shadow:var(--shadow); padding:clamp(1.15rem,3.4vw,2.9rem); margin-bottom:1.5rem;
  max-width:920px; margin-inline:auto;
}
.nb-paper h2,.nb-paper h3,.nb-paper h4{ letter-spacing:-.025em; font-weight:800 }
.cell-md h4{ font-size:1.24rem; margin:2.4rem 0 .9rem; padding-left:.7rem;
  border-left:4px solid var(--blue); line-height:1.4 }
.cell-md p{ margin-bottom:1.05rem }
.cell-md ul,.cell-md ol{ margin-bottom:1.1rem; padding-left:1.35rem }
.cell-md li{ margin-bottom:.42rem }
.cell-md b{ font-weight:800 }
:is(.cell-md,.note-b,.quiz-q,figcaption) code{
  background:var(--blue-s); color:var(--ink); padding:.1em .42em; border-radius:6px;
  font-size:.855em; font-weight:600;
}

/* ── 홈 ──────────────────────────────────── */
.hero{ max-width:920px; margin:0 auto 1.5rem; background:var(--paper);
  border:1px solid var(--line); border-radius:var(--radius); box-shadow:var(--shadow); overflow:hidden }
.hero-img{ width:100%; display:block; border-bottom:1px solid var(--line) }
.hero-body{ padding:clamp(1.3rem,3.6vw,2.7rem) }
.hero h1{ font-size:clamp(1.65rem,4.6vw,2.5rem); font-weight:900; letter-spacing:-.035em;
  line-height:1.33; margin-bottom:.9rem }
.hero-lead{ color:var(--ink-2); font-size:1.03rem; margin-bottom:1.2rem }
.hero-tags{ display:flex; flex-wrap:wrap; gap:.4rem; margin-bottom:1.6rem }
.hero-tags span{ background:var(--page); border:1px solid var(--line); border-radius:99px;
  padding:.24rem .72rem; font-size:.8rem; font-weight:700; color:var(--ink-2) }
.hero-cta{ font-weight:800; border-radius:12px; padding:.62rem 1.5rem; margin-right:.5rem }
.home-h{ font-size:1.35rem; margin-bottom:1.3rem }
.how-grid{ display:grid; grid-template-columns:repeat(auto-fit,minmax(215px,1fr)); gap:.9rem }
.how{ background:var(--page); border:1px solid var(--line); border-radius:13px; padding:1.1rem }
.how span{ font-size:1.7rem; display:block; margin-bottom:.35rem }
.how b{ display:block; margin-bottom:.3rem; font-size:.97rem }
.how p{ font-size:.855rem; color:var(--ink-2); margin:0; line-height:1.62 }
.curriculum{ display:grid; gap:.5rem }
.cur-card{ display:flex; align-items:center; gap:.9rem; padding:.85rem 1rem; border-radius:12px;
  border:1px solid var(--line); background:var(--page); text-decoration:none; color:var(--ink);
  transition:transform .13s,border-color .13s,box-shadow .13s }
.cur-card:hover{ transform:translateX(4px); border-color:var(--blue); box-shadow:var(--shadow) }
.cur-no{ flex:0 0 42px; height:42px; border-radius:11px; background:var(--paper); border:1px solid var(--line);
  display:grid; place-items:center; font-weight:900; color:var(--ink-3); font-size:.92rem }
.cur-card.done .cur-no{ background:var(--mint-s); color:var(--mint); border-color:transparent }
.cur-body{ flex:1; min-width:0 }
.cur-title{ font-weight:800; font-size:.97rem; line-height:1.4 }
.cur-sub{ font-size:.8rem; color:var(--ink-3) }
.cur-check{ opacity:0; color:var(--mint); font-weight:900; font-size:1.1rem }
.cur-card.done .cur-check{ opacity:1 }

/* ── 레슨 머리 ───────────────────────────── */
.lesson-head{ border-bottom:2px solid var(--line); padding-bottom:1.3rem; margin-bottom:1.7rem }
.lh-no{ display:inline-block; background:var(--blue-s); color:var(--blue); font-weight:800;
  font-size:.75rem; padding:.2rem .7rem; border-radius:99px; margin-bottom:.65rem; letter-spacing:.02em }
[data-bs-theme="dark"] .lh-no{ color:#93c5fd }
.lesson-head h1{ font-size:clamp(1.5rem,4.2vw,2.1rem); font-weight:900; letter-spacing:-.035em;
  line-height:1.34; margin-bottom:.4rem }
.lh-sub{ color:var(--ink-3); font-size:1rem; margin:0 }
.lesson-figure{ margin:0 0 2rem }
.lesson-figure img{ width:100%; border-radius:13px; border:1px solid var(--line); display:block }
.lesson-figure figcaption{ text-align:center; font-size:.87rem; color:var(--ink-3); margin-top:.6rem }

/* ── 셀 공통 ─────────────────────────────── */
.cell{ margin-bottom:1.45rem }
.cell-cap{ font-size:.83rem; color:var(--ink-3); margin-bottom:.42rem; font-weight:600 }

/* ── 노트 박스 ───────────────────────────── */
.note{ border-radius:13px; padding:1.05rem 1.2rem; border:1px solid; border-left-width:5px }
.note-h{ font-weight:800; margin-bottom:.5rem; font-size:.99rem }
.note-b{ font-size:.935rem; color:var(--ink-2) }
.note-b ul{ margin:.4rem 0 0; padding-left:1.2rem } .note-b li{ margin-bottom:.35rem }
.note-b p:last-child{ margin-bottom:0 }
.note-tip  { background:var(--blue-s);  border-color:var(--blue) }
.note-warn { background:var(--amber-s); border-color:var(--amber) }
.note-key  { background:var(--mint-s);  border-color:var(--mint) }
.note-story{ background:var(--violet-s);border-color:var(--violet) }
.mini{ background:rgba(15,23,42,.07); border-radius:8px; padding:.6rem .8rem; font-size:.82rem;
  margin:.5rem 0; overflow-x:auto; white-space:pre; line-height:1.6 }
[data-bs-theme="dark"] .mini{ background:rgba(255,255,255,.07) }

/* ── 코드 셀 ─────────────────────────────── */
.cell-code{ border:1px solid var(--line); border-radius:13px; overflow:hidden; background:var(--paper) }
.cell-code .cell-cap{ padding:.6rem .9rem 0; margin:0 }
.code-head{ display:flex; align-items:center; gap:.55rem; padding:.55rem .8rem;
  background:var(--page); border-bottom:1px solid var(--line); flex-wrap:wrap }
.badge-lang{ font-size:.68rem; font-weight:900; padding:.16rem .55rem; border-radius:6px; letter-spacing:.05em }
.badge-sh { background:#0f172a; color:#7fd1b9; letter-spacing:.08em }
[data-bs-theme="dark"] .badge-sh{ background:#020617 }
.run-where{ font-size:.74rem; color:var(--ink-3) }
.btn-run{ background:var(--ink); color:var(--paper); font-weight:800; border-radius:8px;
  padding:.24rem .82rem; font-size:.8rem; border:0; white-space:nowrap }
.btn-run:hover{ opacity:.86; color:var(--paper) }
.btn-run:disabled{ opacity:.45 }
.btn-ghost{ border:1px solid var(--line-2); color:var(--ink-3); border-radius:8px;
  padding:.24rem .55rem; font-size:.8rem; background:transparent }
.btn-ghost:hover{ color:var(--ink); border-color:var(--ink-3) }
.code-area{
  width:100%; border:0; outline:0; resize:none; display:block;
  background:var(--code-bg); color:var(--code-ink);
  padding:.95rem 1.05rem; font-size:.855rem; line-height:1.72; tab-size:4; overflow:hidden;
}
.code-area:focus{ box-shadow:inset 0 0 0 2px var(--blue) }
.cell-out{ border-top:1px solid var(--line); background:var(--page); padding:.8rem 1rem;
  font-size:.85rem; max-height:520px; overflow:auto }
.out-pre{ margin:0; white-space:pre-wrap; font-size:.845rem; line-height:1.68; color:var(--ink) }
.out-err{ color:#dc2626; font-weight:600 }
[data-bs-theme="dark"] .out-err{ color:#f87171 }
.out-msg{ color:var(--mint); font-weight:700; margin:.15rem 0 }
.out-sql{ font-size:.76rem; color:var(--ink-3); margin:.55rem 0 .25rem; white-space:pre-wrap }
.out-meta{ font-size:.74rem; color:var(--ink-3); margin-top:.5rem; text-align:right }
.out-loading{ color:var(--ink-3); font-size:.85rem }
.res-table{ width:100%; border-collapse:collapse; font-size:.82rem; margin:.3rem 0 }
.res-table th{ background:var(--blue-s); font-weight:800; padding:.4rem .65rem;
  border:1px solid var(--line); white-space:nowrap; text-align:left }
.res-table td{ padding:.36rem .65rem; border:1px solid var(--line); background:var(--paper) }
.res-table td.num{ text-align:right; font-variant-numeric:tabular-nums }
.res-table td.null{ color:var(--ink-3); font-style:italic }
.res-wrap{ overflow-x:auto; border-radius:8px }

/* ── 퀴즈 ────────────────────────────────── */
.quiz{ background:var(--violet-s); border:1px solid var(--violet); border-radius:13px; padding:1.15rem 1.25rem }
.quiz-h{ font-weight:900; margin-bottom:.55rem; font-size:.95rem }
.quiz-q{ font-weight:700; margin-bottom:.9rem; line-height:1.62 }
.quiz-opts{ display:grid; gap:.42rem }
.quiz-opt{ display:flex; align-items:flex-start; gap:.65rem; text-align:left; width:100%;
  background:var(--paper); border:1.5px solid var(--line); border-radius:10px;
  padding:.62rem .85rem; font-size:.9rem; color:var(--ink); transition:all .14s; line-height:1.55 }
.quiz-opt:hover:not(:disabled){ border-color:var(--violet); transform:translateX(3px) }
.qo-n{ flex:0 0 22px; height:22px; border-radius:6px; background:var(--page); color:var(--ink-3);
  font-weight:900; font-size:.74rem; display:grid; place-items:center; margin-top:1px }
.quiz-opt.correct{ border-color:var(--mint); background:var(--mint-s) }
.quiz-opt.correct .qo-n{ background:var(--mint); color:#fff }
.quiz-opt.wrong{ border-color:var(--rose); background:var(--rose-s) }
.quiz-opt.wrong .qo-n{ background:var(--rose); color:#fff }
.quiz-explain{ margin-top:.85rem; background:var(--paper); border-radius:10px;
  padding:.75rem .95rem; font-size:.885rem; color:var(--ink-2); line-height:1.68 }

/* ── 레슨 하단 내비 ──────────────────────── */
.lesson-nav{ display:grid; grid-template-columns:1fr auto 1fr; gap:.6rem; align-items:stretch;
  margin-top:2.6rem; padding-top:1.6rem; border-top:2px solid var(--line) }
.ln-btn{ display:flex; flex-direction:column; justify-content:center; gap:.1rem; padding:.75rem 1rem;
  border:1px solid var(--line); border-radius:12px; text-decoration:none; color:var(--ink);
  background:var(--page); transition:border-color .14s,transform .14s; min-width:0 }
.ln-btn:hover{ border-color:var(--blue); transform:translateY(-2px); color:var(--ink) }
.ln-btn small{ color:var(--ink-3); font-size:.73rem; font-weight:700 }
.ln-btn b{ font-size:.88rem; overflow:hidden; text-overflow:ellipsis; white-space:nowrap }
.ln-next{ text-align:right }
.ln-done{ border:0; border-radius:12px; background:var(--mint); color:#fff; font-weight:800;
  padding:.75rem 1.15rem; font-size:.87rem; white-space:nowrap }
.ln-done.is-done{ background:var(--mint-s); color:var(--mint) }
@media (max-width:640px){
  .lesson-nav{ grid-template-columns:1fr 1fr; }
  .ln-done{ grid-column:1/-1; order:-1 }
}

.nb-foot{ text-align:center; color:var(--ink-3); font-size:.85rem; padding:2rem 1rem 0; max-width:920px; margin:0 auto }
.nb-foot p{ margin:.2rem 0 }
.nb-foot .nb-copy{ margin-top:.9rem; padding-top:.9rem; border-top:1px solid var(--line); opacity:.8 }

/* ── 토스트 ──────────────────────────────── */
.nb-toast{ position:fixed; bottom:1.4rem; left:50%; transform:translateX(-50%) translateY(1rem);
  background:var(--ink); color:var(--paper); padding:.62rem 1.15rem; border-radius:11px;
  font-size:.87rem; font-weight:700; z-index:2000; opacity:0; transition:all .25s; box-shadow:var(--shadow) }
.nb-toast.show{ opacity:1; transform:translateX(-50%) translateY(0) }

/* ══════════════════════════════════════════════════════════
   인터랙티브 위젯
   ══════════════════════════════════════════════════════════ */
.widget{ border:1px solid var(--line); border-radius:14px; overflow:hidden; background:var(--paper) }
.widget .cell-cap{ padding:.7rem .95rem 0; margin:0 }
.widget-body{ padding:1rem }
.w-grid{ display:grid; grid-template-columns:1fr 1fr; gap:.9rem }
@media (max-width:780px){ .w-grid{ grid-template-columns:1fr } }
.w-panel{ background:var(--page); border:1px solid var(--line); border-radius:12px; padding:.85rem .95rem }
.w-h{ font-weight:800; font-size:.85rem; margin-bottom:.6rem; display:flex; align-items:center;
  gap:.4rem; justify-content:space-between }
.w-note{ font-size:.78rem; color:var(--ink-3); margin-top:.5rem; line-height:1.6 }
.w-empty{ color:var(--ink-3); font-size:.85rem; text-align:center; padding:1rem 0 }
.w-row{ display:flex; align-items:center; gap:.5rem; margin-bottom:.4rem }
.w-inp{ flex:1; min-width:0; border:1px solid var(--line-2); border-radius:9px;
  padding:.42rem .7rem; font-size:.87rem; background:var(--paper); color:var(--ink) }
.w-inp:focus{ outline:2px solid var(--blue); outline-offset:-1px }
.w-btn{ border:0; border-radius:9px; padding:.42rem .9rem; font-weight:800; font-size:.83rem;
  background:var(--blue); color:#fff; white-space:nowrap }
.w-btn:hover{ filter:brightness(1.08) } .w-btn:disabled{ opacity:.5 }
.w-btn.sec{ background:var(--line); color:var(--ink-2) }
.w-btn.ok{ background:var(--mint) } .w-btn.dan{ background:var(--rose) }
.w-btn.sm{ padding:.22rem .55rem; font-size:.75rem; border-radius:7px }

/* 실행 기록 */
.w-log{ background:var(--code-bg); color:var(--code-ink); border-radius:10px; padding:.7rem .85rem;
  font-family:'JetBrains Mono',monospace; font-size:.745rem; line-height:1.7;
  max-height:290px; overflow:auto; white-space:pre-wrap }
.w-log .lg{ padding:.22rem 0; border-bottom:1px solid rgba(255,255,255,.07) }
.w-log .lg:last-child{ border-bottom:0 }
.w-log .lg-t{ color:#64748b; font-size:.68rem }
.w-log .lg-p{ color:#fbbf24 }
.w-log .lg-new{ animation:flash .8s ease }
@keyframes flash{ from{ background:rgba(59,130,246,.35) } to{ background:transparent } }

/* 할 일 목록 */
.todo-list{ list-style:none; margin:0; padding:0 }
.todo-list li{ display:flex; align-items:center; gap:.6rem; padding:.5rem .2rem;
  border-bottom:1px solid var(--line); font-size:.9rem }
.todo-list li:last-child{ border-bottom:0 }
.todo-list .tid{ color:var(--ink-3); font-size:.72rem; font-family:'JetBrains Mono',monospace; width:20px }
.todo-list .ttl{ flex:1; min-width:0 }
.todo-list li.done .ttl{ text-decoration:line-through; color:var(--ink-3) }
.todo-chk{ width:19px; height:19px; border-radius:6px; border:2px solid var(--line-2);
  background:var(--paper); display:grid; place-items:center; font-size:.72rem; color:#fff; padding:0 }
.todo-list li.done .todo-chk{ background:var(--mint); border-color:var(--mint) }

/* 인덱스 실험실 */
.lab-ctl{ display:flex; flex-wrap:wrap; gap:.5rem; align-items:center; margin-bottom:.8rem }
.lab-res{ display:grid; grid-template-columns:1fr 1fr; gap:.7rem; margin-top:.5rem }
@media (max-width:560px){ .lab-res{ grid-template-columns:1fr } }
.lab-card{ border-radius:12px; padding:.9rem 1rem; border:1.5px solid; text-align:center }
.lab-slow{ background:var(--rose-s);  border-color:var(--rose) }
.lab-fast{ background:var(--mint-s);  border-color:var(--mint) }
.lab-card b{ display:block; font-size:.85rem; margin-bottom:.15rem }
.lab-time{ font-size:1.65rem; font-weight:900; font-variant-numeric:tabular-nums; line-height:1.25 }
.lab-card small{ color:var(--ink-2); font-size:.74rem }
.lab-verdict{ text-align:center; font-weight:800; margin-top:.75rem; padding:.7rem;
  background:var(--amber-s); border-radius:11px; font-size:.93rem }
.lab-bar{ height:11px; border-radius:99px; background:var(--line); overflow:hidden; margin-top:.45rem }
.lab-bar i{ display:block; height:100%; border-radius:99px; transition:width .7s ease }

.w-alert{ background:var(--rose-s); color:var(--rose); border-radius:9px; padding:.5rem .75rem;
  font-size:.83rem; font-weight:700; margin-bottom:.6rem }
.w-ok{ background:var(--mint-s); color:var(--mint); border-radius:9px; padding:.5rem .75rem;
  font-size:.83rem; font-weight:700; margin-bottom:.6rem }
/* 계정 · 랜딩 · 관리자 */
.nb-user{ font-size:.8rem; font-weight:700; color:var(--ink-2); padding:.2rem .55rem;
  background:var(--page); border:1px solid var(--line); border-radius:99px; white-space:nowrap }
.nb-user b{ color:var(--rose) }
.nb-user.guest{ color:var(--ink-3) }
.landing{ max-width:820px; margin:2rem auto; text-align:center; padding:0 1rem }
.landing-img{ width:100%; max-width:620px; border-radius:var(--radius); box-shadow:var(--shadow) }
.landing h1{ font-size:1.9rem; font-weight:900; margin:1.4rem 0 .5rem; letter-spacing:-.02em }
.landing-lead{ color:var(--ink-2); line-height:1.85; font-size:.97rem; margin-bottom:1.6rem }
.landing-grid{ display:grid; grid-template-columns:repeat(auto-fit,minmax(255px,1fr)); gap:.9rem }
.lp-card{ display:block; text-align:left; text-decoration:none; color:inherit; padding:1.2rem 1.3rem;
  border-radius:var(--radius); border:2px solid var(--line); background:var(--paper); transition:.15s }
.lp-card:hover{ transform:translateY(-2px); box-shadow:var(--shadow) }
.lp-login{ border-color:var(--blue); background:var(--blue-s) }
.lp-guest{ border-color:var(--line-2) }
.lp-i{ font-size:2rem } .lp-card b{ display:block; font-size:1.05rem; margin:.3rem 0 .5rem }
.lp-card ul{ margin:0 0 .8rem; padding-left:1.1rem; font-size:.85rem; color:var(--ink-2); line-height:1.9 }
.lp-go{ font-weight:800; font-size:.87rem; color:var(--blue) }
.lp-guest .lp-go{ color:var(--ink-3) }
.landing-foot{ margin-top:1.4rem; font-size:.82rem; color:var(--ink-3) }
.login-box{ max-width:400px; margin:2.5rem auto; text-align:center }
.login-form{ display:grid; gap:.8rem; margin:1.2rem 0 .8rem; text-align:left }
.login-form label{ font-size:.82rem; font-weight:800; color:var(--ink-2); display:grid; gap:.25rem }
.login-alt{ font-size:.84rem } .login-alt a{ color:var(--ink-3) }
.locked-box{ max-width:520px; margin:2.5rem auto; text-align:center }
.lk-icon{ font-size:3rem } .lk-msg{ margin:1rem 0 1.4rem; line-height:1.9; color:var(--ink-2) }
.lk-btns{ display:flex; gap:.5rem; justify-content:center; flex-wrap:wrap }
.toc-item.locked, .cur-card.locked{ opacity:.55 }
.guest-note{ border-left:4px solid var(--amber) }
.guest-note p{ margin:.3rem 0 0; font-size:.87rem; color:var(--ink-2); line-height:1.75 }
.quiz-score{ margin-top:.7rem; font-size:.83rem; color:var(--ink-2); background:var(--page);
  border:1px solid var(--line); border-radius:99px; padding:.25rem .8rem; display:inline-block }
.ms-sum{ font-size:.95rem; margin-bottom:.7rem }
.ms-sum b{ font-size:1.15rem } .ms-pct{ color:var(--ink-3); margin-left:.4rem }
.ms-grid{ display:grid; grid-template-columns:repeat(auto-fill,minmax(64px,1fr)); gap:.35rem }
.ms-cell{ text-align:center; text-decoration:none; color:var(--ink-3); background:var(--page);
  border:1.5px solid var(--line); border-radius:9px; padding:.35rem .1rem; font-size:.7rem }
.ms-cell b{ display:block; font-size:.82rem; color:var(--ink) }
.ms-cell.part{ background:var(--amber-s); border-color:var(--amber) }
.ms-cell.full{ background:var(--mint-s); border-color:var(--mint) }
.ad-head{ display:flex; flex-wrap:wrap; align-items:center; gap:.8rem; margin-bottom:1rem }
.ad-tabs{ display:flex; gap:.3rem; margin-left:auto }
.ad-tab{ font:inherit; font-size:.82rem; font-weight:700; padding:.35rem .8rem; cursor:pointer;
  border-radius:9px; background:var(--page); border:1.5px solid var(--line); color:var(--ink-2) }
.ad-tab.on{ background:var(--blue); border-color:var(--blue); color:#fff }
.ad-add, .ad-toolbar{ display:flex; flex-wrap:wrap; gap:.4rem; align-items:center; margin-bottom:.8rem }
.ad-table{ font-size:.83rem } .ad-table td{ vertical-align:middle }
.ad-in{ font-size:.8rem; padding:.25rem .45rem; max-width:130px }
.ad-num{ width:70px; font-size:.8rem; padding:.25rem .4rem }
.ad-dim{ color:var(--ink-3); font-size:.76rem }
.ad-actions{ display:flex; gap:.25rem; flex-wrap:wrap }
.ad-h{ margin-top:1.4rem }
.ad-matrix{ overflow-x:auto }
.ad-matrix-t{ font-size:.75rem; white-space:nowrap }
.ad-matrix-t td, .ad-matrix-t th{ padding:.2rem .35rem; text-align:center }
.ad-name{ font-weight:800; text-align:left!important }
.mx-full{ background:var(--mint-s); font-weight:800 }
.mx-part{ background:var(--amber-s) }
.mx-none{ color:var(--ink-3) }

/* ══════════════════════════════════════════════════════════
   목차 · 커리큘럼의 부(部) 구분
   ══════════════════════════════════════════════════════════ */
.toc-part{ font-size:.7rem; font-weight:900; color:var(--ink-3); letter-spacing:.08em;
  padding:.9rem .6rem .3rem; list-style:none }
.toc-part:first-child{ padding-top:.2rem }
.cur-part{ font-size:.78rem; font-weight:900; color:var(--ink-3); letter-spacing:.06em;
  margin:1.1rem 0 .2rem; padding-left:.2rem }
.cur-part:first-child{ margin-top:0 }

/* ══════════════════════════════════════════════════════════
   레슨 본문 전용 요소
   ══════════════════════════════════════════════════════════ */
.plain-block{ background:var(--code-bg); color:var(--code-ink); border-radius:11px;
  padding:.95rem 1.1rem; font-size:.82rem; line-height:1.75; overflow-x:auto; margin:.8rem 0 1.1rem;
  font-family:'JetBrains Mono','D2Coding',monospace; white-space:pre }

/* 프롬프트 미리보기 */
.term-demo{ background:var(--code-bg); border-radius:11px; padding:1rem 1.15rem; margin:1.1rem 0;
  font-family:'JetBrains Mono','D2Coding',monospace; font-size:.95rem; letter-spacing:.01em }
.tp-u{ color:#7fd1b9; font-weight:700 } .tp-h{ color:#6aa9e9; font-weight:700 }
.tp-p{ color:#f6d365; font-weight:700 } .tp-s{ color:#94a3b8 }
.tp-cur{ color:#e2e8f0; animation:blink 1.1s step-end infinite }
@keyframes blink{ 50%{ opacity:0 } }

.prompt-anatomy,.perm-anatomy{ display:grid; gap:.42rem; margin:1rem 0 1.3rem }
.pa-item,.pm{ display:flex; align-items:baseline; gap:.8rem; background:var(--page);
  border:1px solid var(--line); border-left:4px solid var(--blue); border-radius:10px;
  padding:.55rem .85rem; font-size:.87rem }
.pa-item b,.pm code{ flex:0 0 92px; font-family:'JetBrains Mono','D2Coding',monospace;
  font-weight:800; font-size:.9rem; background:none!important; padding:0!important }
.pa-item span,.pm span{ color:var(--ink-2); font-size:.85rem }
.perm-anatomy{ grid-template-columns:repeat(auto-fit,minmax(215px,1fr)) }
.pm{ flex-direction:column; gap:.15rem; align-items:flex-start }
.pm b{ font-size:.88rem } .pm code{ flex:none; font-size:1.02rem; color:var(--ink) }
.pm-u{ border-left-color:var(--mint) } .pm-g{ border-left-color:var(--amber) }
.pm-o{ border-left-color:var(--rose) }

/* 경로 · 명령 설명 목록 */
.dir-map{ display:grid; grid-template-columns:repeat(auto-fit,minmax(255px,1fr));
  gap:.5rem; margin:1.1rem 0 1.3rem }
.dm{ background:var(--page); border:1px solid var(--line); border-radius:11px; padding:.7rem .9rem }
.dm code{ display:inline-block; font-family:'JetBrains Mono','D2Coding',monospace; font-weight:800;
  font-size:.83rem; background:var(--blue-s)!important; color:var(--ink); padding:.1rem .45rem!important;
  border-radius:6px; margin-bottom:.28rem }
.dm b{ display:block; font-size:.9rem; margin-bottom:.1rem }
.dm span{ display:block; font-size:.8rem; color:var(--ink-3); line-height:1.6 }

/* 파이프 */
.pipe-demo{ background:var(--code-bg); border-radius:12px; padding:1.05rem 1.15rem; margin:1.1rem 0;
  text-align:center; font-family:'JetBrains Mono','D2Coding',monospace }
.pd-cmd{ display:inline-block; background:rgba(127,209,185,.16); color:#7fd1b9; border-radius:7px;
  padding:.22rem .6rem; font-size:.83rem; margin:.15rem 0 }
.pd-op{ color:#f4a259; font-weight:900; margin:0 .45rem; font-size:1rem }
.pd-say{ color:#94a3b8; font-size:.82rem; margin-top:.7rem; font-family:inherit;
  font-family:'Pretendard Variable',Pretendard,sans-serif }
.pipe-steps{ display:grid; gap:.4rem; margin:1.1rem 0 1.3rem }
.ps{ display:flex; align-items:baseline; gap:.85rem; background:var(--page); border-radius:10px;
  border-left:4px solid var(--coral); padding:.55rem .9rem; flex-wrap:wrap }
.ps code{ font-family:'JetBrains Mono','D2Coding',monospace; font-weight:800; font-size:.82rem;
  background:none!important; padding:0!important; color:var(--ink); flex:0 0 auto; min-width:170px }
.ps span{ font-size:.84rem; color:var(--ink-2) }

/* 요청 흐름 사슬 */
.flow-chain{ display:flex; align-items:stretch; justify-content:center; gap:.35rem;
  flex-wrap:wrap; margin:1.3rem 0 }
.fc{ background:var(--page); border:1.5px solid var(--line-2); border-radius:12px;
  padding:.7rem .9rem; text-align:center; font-size:1.5rem; line-height:1.2; min-width:120px }
.fc b{ display:block; font-size:.87rem; margin-top:.2rem }
.fc span{ display:block; font-size:.72rem; color:var(--ink-3); font-family:'JetBrains Mono',monospace }
.fc-hi{ background:var(--mint-s); border-color:var(--mint) }
.fc-a{ align-self:center; color:var(--ink-3); font-weight:800 }

/* 크론 표현식 */
.cron-anatomy{ background:var(--code-bg); color:var(--code-ink); border-radius:12px;
  padding:1rem 1.2rem; margin:1.1rem 0; font-size:.83rem; line-height:1.75; overflow-x:auto;
  font-family:'JetBrains Mono','D2Coding',monospace }

.finale{ text-align:center; font-size:1.02rem; line-height:1.95;
  background:linear-gradient(135deg,var(--violet-s),var(--mint-s));
  border-radius:14px; padding:1.3rem 1.2rem; margin:1.4rem 0 }

/* ══════════════════════════════════════════════════════════
   터미널
   ══════════════════════════════════════════════════════════ */
.term-wrap{ border-radius:12px; overflow:hidden; border:1px solid var(--line-2); background:#0b1017 }
.term-bar{ display:flex; align-items:center; gap:.5rem; padding:.45rem .8rem; background:#131b26;
  border-bottom:1px solid #1f2937; font-size:.74rem; color:#94a3b8 }
.term-dots{ display:flex; gap:.32rem }
.term-dots i{ width:10px; height:10px; border-radius:99px; display:block }
.term-dots i:nth-child(1){ background:#ef4444 } .term-dots i:nth-child(2){ background:#f59e0b }
.term-dots i:nth-child(3){ background:#10b981 }
.term-title{ font-family:'JetBrains Mono',monospace }
.term-tools{ margin-left:auto; display:flex; gap:.3rem }
.term-tools button{ background:#1f2937; color:#cbd5e1; border:0; border-radius:6px;
  padding:.15rem .5rem; font-size:.7rem; font-weight:700 }
.term-tools button:hover{ background:#334155; color:#fff }
.term-screen{ font-family:'JetBrains Mono','D2Coding',monospace; font-size:.815rem; line-height:1.68;
  color:#d7dee8; padding:.85rem .95rem; height:340px; overflow-y:auto; white-space:pre-wrap;
  word-break:break-all; overflow-wrap:anywhere }
.term-screen.tall{ height:440px }
.term-screen::-webkit-scrollbar{ width:8px }
.term-screen::-webkit-scrollbar-thumb{ background:#334155; border-radius:9px }
.term-line{ white-space:pre-wrap }
.term-echo{ color:#e2e8f0 }
.term-echo .tp-u{ color:#7fd1b9 } .term-echo .tp-h{ color:#6aa9e9 } .term-echo .tp-p{ color:#f6d365 }
.term-err{ color:#fca5a5 }
.term-hint{ color:#64748b; font-style:italic }
.term-input{ display:flex; align-items:baseline; gap:.45rem; padding:.15rem 0 }
.term-input .tin{ flex:1; min-width:0; background:transparent; border:0; outline:0; color:#e2e8f0;
  font-family:inherit; font-size:inherit; padding:0 }
.term-foot{ display:flex; gap:.6rem; flex-wrap:wrap; padding:.5rem .8rem; background:#131b26;
  border-top:1px solid #1f2937; font-size:.71rem; color:#64748b }
.term-foot b{ color:#94a3b8 }
.term-chips{ display:flex; flex-wrap:wrap; gap:.3rem; margin-top:.6rem }
.term-chip{ background:var(--page); border:1px solid var(--line-2); border-radius:99px;
  padding:.2rem .65rem; font-size:.74rem; font-weight:700; color:var(--ink-2);
  font-family:'JetBrains Mono',monospace }
.term-chip:hover{ background:var(--blue-s); border-color:var(--blue); color:var(--ink) }

/* 셸 셀 출력 */
.sh-out{ font-family:'JetBrains Mono','D2Coding',monospace; font-size:.8rem; line-height:1.68;
  white-space:pre-wrap; word-break:break-all; overflow-wrap:anywhere; margin:0 }
.sh-prompt{ color:var(--ink-3); font-weight:700 }
.sh-status{ font-size:.72rem; color:var(--ink-3); margin-top:.45rem; text-align:right }
.sh-status.bad{ color:var(--rose); font-weight:700 }

/* ══════════════════════════════════════════════════════════
   nano 편집기
   ══════════════════════════════════════════════════════════ */
.nano-modal{ position:fixed; inset:0; background:rgba(2,6,23,.72); z-index:3000;
  display:flex; align-items:center; justify-content:center; padding:1rem }
.nano-win{ width:min(760px,100%); background:#0b1017; border-radius:12px; overflow:hidden;
  box-shadow:0 24px 70px rgba(0,0,0,.5); display:flex; flex-direction:column; max-height:88vh }
.nano-top{ background:#d7dee8; color:#0b1017; font-size:.8rem; padding:.4rem .9rem;
  display:flex; gap:.9rem; font-family:'JetBrains Mono',monospace }
.nano-top span{ opacity:.75; overflow:hidden; text-overflow:ellipsis; white-space:nowrap }
.nano-area{ flex:1; min-height:300px; background:#0b1017; color:#d7dee8; border:0; outline:0;
  resize:none; padding:.9rem 1rem; font-family:'JetBrains Mono','D2Coding',monospace;
  font-size:.83rem; line-height:1.7; tab-size:4 }
.nano-status{ min-height:1.7rem; padding:.2rem .9rem; font-size:.78rem; text-align:center;
  font-family:'JetBrains Mono',monospace; color:#0b1017; background:transparent }
.nano-status.on{ background:#d7dee8 }
.nano-keys{ display:grid; grid-template-columns:repeat(auto-fit,minmax(130px,1fr)); gap:1px;
  background:#1f2937 }
.nano-keys button{ background:#0b1017; color:#d7dee8; border:0; padding:.5rem .4rem;
  font-size:.76rem; font-family:'JetBrains Mono',monospace; text-align:left; padding-left:.9rem }
.nano-keys button:hover{ background:#1f2937 }
.nano-keys b{ background:#d7dee8; color:#0b1017; padding:0 .25rem; margin-right:.4rem; font-weight:700 }

/* ══════════════════════════════════════════════════════════
   위젯 공통 추가분
   ══════════════════════════════════════════════════════════ */
.w-seg{ display:flex; flex-wrap:wrap; gap:.3rem; margin-bottom:.7rem }
.w-seg button{ font:inherit; font-size:.79rem; font-weight:700; padding:.3rem .75rem;
  border-radius:9px; background:var(--page); border:1.5px solid var(--line); color:var(--ink-2) }
.w-seg button.on{ background:var(--blue); border-color:var(--blue); color:#fff }
.w-kv{ display:flex; justify-content:space-between; gap:.6rem; font-size:.83rem;
  padding:.28rem 0; border-bottom:1px dashed var(--line) }
.w-kv:last-child{ border-bottom:0 }
.w-kv b{ font-variant-numeric:tabular-nums }
.w-bar{ height:14px; border-radius:99px; background:var(--line); overflow:hidden; margin:.3rem 0 }
.w-bar i{ display:block; height:100%; border-radius:99px; transition:width .45s ease }
.w-mono{ font-family:'JetBrains Mono','D2Coding',monospace }
.w-chip{ display:inline-block; font-size:.7rem; font-weight:800; padding:.12rem .5rem;
  border-radius:6px; background:var(--line); color:var(--ink-2); margin-right:.3rem }
.w-chip.ok{ background:var(--mint-s); color:var(--mint) }
.w-chip.no{ background:var(--rose-s); color:var(--rose) }
.w-chip.warn{ background:var(--amber-s); color:var(--amber) }
.w-hint{ font-size:.8rem; color:var(--ink-2); background:var(--page); border-radius:9px;
  border-left:3px solid var(--blue); padding:.5rem .75rem; margin-top:.6rem; line-height:1.65 }

/* 1강 · OS 실험실 */
.os-stage{ display:grid; grid-template-columns:1fr auto 1fr; gap:.6rem; align-items:center }
@media (max-width:640px){ .os-stage{ grid-template-columns:1fr } }
.os-apps{ display:grid; gap:.4rem }
.os-app{ background:var(--paper); border:1.5px solid var(--line-2); border-radius:11px;
  padding:.5rem .7rem; font-size:.84rem; font-weight:700; display:flex; gap:.5rem; align-items:center }
.os-app small{ margin-left:auto; font-weight:600; font-size:.72rem; color:var(--ink-3) }
.os-app.angry{ border-color:var(--rose); background:var(--rose-s); animation:shake .4s }
@keyframes shake{ 25%{ transform:translateX(-3px) } 75%{ transform:translateX(3px) } }
.os-mid{ text-align:center; font-size:.78rem; font-weight:800; color:var(--ink-3) }
.os-kernel{ background:var(--mint-s); border:1.5px solid var(--mint); border-radius:11px;
  padding:.6rem; font-size:.83rem; font-weight:800 }
.os-hw{ background:var(--page); border:1.5px dashed var(--line-2); border-radius:11px;
  padding:.7rem; display:grid; gap:.35rem }
.os-res{ display:flex; align-items:center; gap:.5rem; font-size:.8rem }
.os-res b{ flex:0 0 62px }
.os-res .w-bar{ flex:1; margin:0 }

/* 2강 · 부팅 순서 */
.boot-list{ display:grid; gap:.4rem; margin-bottom:.7rem }
.boot-item{ display:flex; align-items:center; gap:.7rem; background:var(--paper);
  border:1.5px solid var(--line-2); border-radius:11px; padding:.6rem .8rem;
  font-size:.85rem; text-align:left; width:100% }
.boot-item.ok{ background:var(--mint-s); border-color:var(--mint) }
.boot-item.bad{ background:var(--rose-s); border-color:var(--rose) }
.boot-n{ flex:0 0 26px; height:26px; border-radius:8px; background:var(--page);
  display:grid; place-items:center; font-weight:900; font-size:.78rem; color:var(--ink-3) }
.boot-item b{ display:block } .boot-item small{ color:var(--ink-3); font-size:.75rem }

/* 3강 · 명령 해부 */
.cmd-parts{ display:flex; flex-wrap:wrap; gap:.4rem; align-items:stretch; margin-bottom:.8rem }
.cmd-part{ border-radius:11px; padding:.5rem .7rem; border:1.5px solid; min-width:104px;
  font-family:'JetBrains Mono',monospace }
.cmd-part small{ display:block; font-family:'Pretendard Variable',sans-serif;
  font-size:.68rem; font-weight:800; opacity:.8; margin-bottom:.15rem }
.cp-cmd{ background:var(--mint-s); border-color:var(--mint) }
.cp-opt{ background:var(--amber-s); border-color:var(--amber) }
.cp-arg{ background:var(--blue-s); border-color:var(--blue) }

/* 4강 · 트리 탐험 */
.tree-path{ font-family:'JetBrains Mono',monospace; font-size:.85rem; font-weight:800;
  background:var(--code-bg); color:#7fd1b9; border-radius:9px; padding:.45rem .8rem; margin-bottom:.6rem;
  overflow-x:auto; white-space:nowrap }
.tree-list{ display:grid; gap:.22rem; max-height:290px; overflow:auto }
.tree-row{ display:flex; align-items:center; gap:.55rem; background:var(--paper);
  border:1px solid var(--line); border-radius:9px; padding:.34rem .6rem; font-size:.83rem;
  text-align:left; width:100%; font-family:'JetBrains Mono',monospace }
.tree-row:hover{ border-color:var(--blue); background:var(--blue-s) }
.tree-row .ti{ flex:0 0 18px } .tree-row .tn{ flex:1; min-width:0; overflow:hidden; text-overflow:ellipsis }
.tree-row .tm{ font-size:.7rem; color:var(--ink-3) }
.tree-row.up{ background:var(--page) }

/* 7강 · 권한 계산기 */
.perm-grid{ display:grid; grid-template-columns:repeat(3,1fr); gap:.5rem; margin-bottom:.7rem }
.perm-col{ background:var(--page); border:1.5px solid var(--line); border-radius:11px; padding:.6rem;
  text-align:center }
.perm-col h6{ font-size:.78rem; font-weight:900; margin-bottom:.4rem }
.perm-chk{ display:flex; justify-content:center; gap:.3rem }
.perm-chk button{ width:32px; height:32px; border-radius:8px; border:1.5px solid var(--line-2);
  background:var(--paper); font-weight:900; font-size:.85rem; color:var(--ink-3);
  font-family:'JetBrains Mono',monospace }
.perm-chk button.on{ background:var(--mint); border-color:var(--mint); color:#fff }
.perm-out{ text-align:center; font-family:'JetBrains Mono',monospace; font-size:1.5rem;
  font-weight:900; letter-spacing:.06em; background:var(--code-bg); color:#7fd1b9;
  border-radius:11px; padding:.7rem; margin-bottom:.3rem }
.perm-num{ text-align:center; font-size:1.05rem; font-weight:900; color:var(--blue) }

/* 8강 · 스케줄러 */
.sched-track{ display:grid; gap:.3rem; margin:.6rem 0 }
.sched-row{ display:flex; align-items:center; gap:.5rem; font-size:.78rem }
.sched-row b{ flex:0 0 86px; overflow:hidden; text-overflow:ellipsis; white-space:nowrap }
.sched-lane{ flex:1; display:flex; gap:1px; height:20px; background:var(--line); border-radius:5px; overflow:hidden }
.sched-lane i{ flex:1; display:block; background:transparent }
.sched-lane i.on{ background:var(--blue) }
.sched-lane i.now{ background:var(--coral) }
.sched-cpu{ text-align:center; font-size:.83rem; font-weight:800; background:var(--amber-s);
  border-radius:9px; padding:.4rem; margin-top:.5rem }

/* 9강 · 메모리 */
.mem-bar{ display:flex; height:34px; border-radius:9px; overflow:hidden; border:1px solid var(--line-2);
  background:var(--page); margin:.5rem 0 }
.mem-seg{ display:grid; place-items:center; font-size:.68rem; font-weight:800; color:#fff;
  overflow:hidden; white-space:nowrap; transition:width .35s ease }
.mem-free{ background:var(--line); color:var(--ink-3) }

/* 10강 · 파이프 조립기 */
.pipe-build{ display:flex; flex-wrap:wrap; align-items:center; gap:.35rem; min-height:44px;
  background:var(--code-bg); border-radius:10px; padding:.55rem .7rem; margin-bottom:.6rem }
.pipe-tok{ background:rgba(127,209,185,.16); color:#7fd1b9; border-radius:7px; padding:.2rem .55rem;
  font-family:'JetBrains Mono',monospace; font-size:.78rem; border:0 }
.pipe-tok:hover{ background:rgba(239,68,68,.22); color:#fca5a5 }
.pipe-sep{ color:#f4a259; font-weight:900 }
.pipe-empty{ color:#64748b; font-size:.78rem; font-style:italic }

/* 12강 · 패키지 */
.pkg-list{ display:grid; gap:.32rem; max-height:250px; overflow:auto }
.pkg{ display:flex; align-items:center; gap:.5rem; background:var(--paper); border:1px solid var(--line);
  border-radius:9px; padding:.38rem .65rem; font-size:.82rem }
.pkg b{ flex:1; font-family:'JetBrains Mono',monospace; font-size:.8rem }
.pkg.dep{ margin-left:1.2rem; border-style:dashed; font-size:.78rem; opacity:.9 }

/* 13강 · 권한 매트릭스 */
.mx-table{ width:100%; border-collapse:collapse; font-size:.8rem }
.mx-table th{ background:var(--page); font-weight:800; padding:.4rem .5rem; border:1px solid var(--line);
  font-family:'JetBrains Mono',monospace; font-size:.74rem }
.mx-table td{ padding:.35rem .5rem; border:1px solid var(--line); text-align:center; font-weight:800 }
.mx-y{ background:var(--mint-s); color:var(--mint) }
.mx-n{ background:var(--rose-s); color:var(--rose) }
.mx-table td.mx-file{ text-align:left; font-family:'JetBrains Mono',monospace;
  font-weight:600; background:var(--paper); font-size:.75rem }

/* 14·18강 · 단계 목록 */
.step-list{ display:grid; gap:.4rem }
.step{ display:flex; align-items:center; gap:.7rem; background:var(--paper); border:1.5px solid var(--line);
  border-radius:11px; padding:.55rem .8rem; font-size:.84rem; text-align:left; width:100% }
.step.done{ background:var(--mint-s); border-color:var(--mint) }
.step.fail{ background:var(--rose-s); border-color:var(--rose) }
.step .sn{ flex:0 0 24px; height:24px; border-radius:7px; background:var(--page); display:grid;
  place-items:center; font-weight:900; font-size:.74rem; color:var(--ink-3) }
.step b{ display:block } .step small{ color:var(--ink-3); font-size:.74rem }

/* 15강 · 서비스 */
.svc-card{ background:var(--page); border:1.5px solid var(--line); border-radius:12px;
  padding:.75rem .9rem; margin-bottom:.5rem }
.svc-card.up{ border-color:var(--mint); background:var(--mint-s) }
.svc-card.down{ border-color:var(--rose); background:var(--rose-s) }
.svc-h{ display:flex; align-items:center; gap:.5rem; font-weight:800; font-size:.9rem }
.svc-h small{ margin-left:auto; font-weight:700; font-size:.72rem }
.svc-btns{ display:flex; gap:.3rem; flex-wrap:wrap; margin-top:.5rem }

/* 16강 · 라우팅 */
.route-res{ border-radius:11px; padding:.8rem .95rem; font-size:.86rem; border:1.5px solid;
  margin-top:.6rem; line-height:1.7 }
.route-200{ background:var(--mint-s); border-color:var(--mint) }
.route-40x{ background:var(--amber-s); border-color:var(--amber) }
.route-50x{ background:var(--rose-s); border-color:var(--rose) }
.route-code{ font-size:1.35rem; font-weight:900; font-family:'JetBrains Mono',monospace }

/* 17강 · 로그 문제 */
.qtask{ background:var(--page); border-left:4px solid var(--violet); border-radius:10px;
  padding:.7rem .9rem; margin-bottom:.6rem; font-size:.87rem }
.qtask b{ display:block; margin-bottom:.2rem }

/* 19강 · 크론 */
.cron-fields{ display:grid; grid-template-columns:repeat(5,1fr); gap:.4rem; margin-bottom:.6rem }
.cron-f{ text-align:center }
.cron-f label{ display:block; font-size:.7rem; font-weight:800; color:var(--ink-3); margin-bottom:.2rem }
.cron-f input{ width:100%; text-align:center; font-family:'JetBrains Mono',monospace;
  font-size:.9rem; font-weight:800; border:1.5px solid var(--line-2); border-radius:9px;
  padding:.35rem .2rem; background:var(--paper); color:var(--ink) }
.cron-say{ background:var(--mint-s); border:1.5px solid var(--mint); border-radius:11px;
  padding:.7rem .9rem; font-size:.92rem; font-weight:800; text-align:center }
.cron-say.bad{ background:var(--rose-s); border-color:var(--rose) }

/* 20강 · 보안 점검 */
.sec-list{ display:grid; gap:.4rem }
.sec-item{ display:flex; align-items:flex-start; gap:.65rem; background:var(--paper);
  border:1px solid var(--line); border-radius:11px; padding:.6rem .8rem; font-size:.85rem }
.sec-item.pass{ background:var(--mint-s); border-color:var(--mint) }
.sec-item.fail{ background:var(--rose-s); border-color:var(--rose) }
.sec-ico{ font-size:1.05rem; line-height:1.4 }
.sec-item b{ display:block } .sec-item small{ color:var(--ink-2); font-size:.78rem; line-height:1.6 }
.sec-score{ text-align:center; font-size:1.05rem; font-weight:900; background:var(--page);
  border-radius:11px; padding:.7rem; margin-bottom:.7rem }

/* ── 허브(drson.iotok.org)로 돌아가는 홈 버튼 ── */
.nb-home{
  flex:0 0 auto; font-weight:700; line-height:1.4;
  border-radius:10px; padding:.28rem .55rem; white-space:nowrap;
}
@media (max-width:575.98px){ .nb-home{ padding:.28rem .45rem } }


/* 언어 토글 — 오른쪽 위. 지금 누르면 갈 언어를 배지로 보여 준다.
   좁은 화면에서는 지구본만 남긴다. */
.nb-lang{ display:inline-flex; align-items:center; gap:.25rem; font-weight:700; text-decoration:none }
.nb-lang b{ font-weight:800; font-size:.82rem; letter-spacing:.02em }
@media (max-width:520px){ .nb-lang b{ display:none } }

/* 영어로 보는데 그 강의 본문이 아직 한국어일 때 띄우는 한 줄 */
.nb-koronly{
  margin:0 0 1rem; padding:.55rem .85rem; border-radius:.5rem;
  border:1px solid var(--bs-warning-border-subtle,#ffe69c);
  background:var(--bs-warning-bg-subtle,#fff3cd);
  color:var(--bs-warning-text-emphasis,#664d03);
  font-size:.88rem;
}


/* ── 레슨 머리 — 눈높이 토글을 오른쪽에 앉힌다 ── */
.lh-top{ display:flex; align-items:center; justify-content:space-between;
  gap:.6rem; flex-wrap:wrap; margin-bottom:.65rem }
.lh-top .lh-no{ margin-bottom:0 }

/* ── 눈높이 토글 · 고등학생 풀이 ───────────
   강마다 오른쪽 위의 토글이 <html data-level> 을 바꾼다.
   기본은 'uni' — 그때 .cell-hs 는 아예 그려지지 않는다.
   ────────────────────────────────────────── */
.lvl-toggle{ display:inline-flex; background:var(--page); border:1px solid var(--line-2);
  border-radius:99px; padding:3px; gap:2px; flex:0 0 auto }
.lvl-btn{ border:0; background:transparent; color:var(--ink-3); font-weight:800;
  font-size:.78rem; letter-spacing:-.01em; padding:.26rem .82rem; border-radius:99px;
  white-space:nowrap; line-height:1.5; transition:background .18s, color .18s }
.lvl-btn:hover{ color:var(--ink-2) }
html[data-level="hs"]  .lvl-btn[data-level="hs"],
html[data-level="uni"] .lvl-btn[data-level="uni"]{
  background:var(--paper); color:var(--ink); box-shadow:0 1px 2px rgba(15,23,42,.12) }
html[data-level="hs"] .lvl-btn[data-level="hs"]{ color:var(--coral) }
[data-bs-theme="dark"] .lvl-btn[data-level]{ box-shadow:none }
html[data-bs-theme="dark"][data-level="hs"] .lvl-btn[data-level="hs"]{ color:#fdba74 }

html[data-level="uni"] .cell-hs{ display:none }
.cell-hs{ border:1px solid var(--coral); border-left-width:5px; border-radius:13px;
  background:var(--coral-s); padding:1.05rem 1.2rem }
.hs-h{ font-weight:800; font-size:.99rem; margin-bottom:.55rem;
  display:flex; align-items:center; gap:.5rem; flex-wrap:wrap }
.hs-badge{ background:var(--coral); color:#fff; font-size:.68rem; font-weight:900;
  padding:.14rem .5rem; border-radius:6px; letter-spacing:.02em; white-space:nowrap }
.hs-b{ font-size:.95rem; color:var(--ink-2) }
.hs-b p{ margin-bottom:.7rem } .hs-b p:last-child{ margin-bottom:0 }
.hs-b ul,.hs-b ol{ margin:.4rem 0 .7rem; padding-left:1.25rem }
.hs-b li{ margin-bottom:.35rem }
.hs-b b{ color:var(--ink) }
.hs-q{ font-weight:800; color:var(--ink); margin:.9rem 0 .35rem }
.hs-eq{ background:var(--paper); border:1px dashed var(--coral); border-radius:10px;
  padding:.7rem .9rem; margin:.7rem 0; font-weight:700; color:var(--ink); text-align:center }
.hs-b table{ width:100%; border-collapse:collapse; margin:.7rem 0; font-size:.88rem }
.hs-b th,.hs-b td{ border:1px solid var(--line); padding:.42rem .6rem; text-align:left }
.hs-b th{ background:var(--paper); font-weight:800; color:var(--ink) }
[data-bs-theme="dark"] .hs-eq,[data-bs-theme="dark"] .hs-b th{ background:rgba(255,255,255,.04) }