/* =========================================================
   Design tokens
   ========================================================= */
:root {
  --bg: #fafaf9;
  --bg-elev: #ffffff;
  --bg-sunken: #f4f4f2;
  --bg-hover: #f0efec;
  --border: #e7e5e2;
  --border-strong: #d6d3cf;
  --text: #1c1917;
  --text-2: #44403c;
  --muted: #78716c;
  --faint: #a8a29e;
  --accent: #ea580c;
  --accent-strong: #c2410c;
  --accent-soft: #fff4ed;
  --accent-ring: rgba(234, 88, 12, .22);
  --link: #c2410c;
  --ok: #15803d; --ok-soft: #f0fdf4; --ok-line: #bbf7d0;
  --warn: #b45309; --warn-soft: #fffbeb; --warn-line: #fde68a;
  --tip: #1d4ed8; --tip-soft: #eff6ff; --tip-line: #bfdbfe;
  --bad: #b91c1c; --bad-soft: #fef2f2; --bad-line: #fecaca;
  --note-soft: #fff7f2; --note-line: #fed7c3;
  --term-bg: #0f1013; --term-bar: #1a1b20; --term-text: #d4d4d8;
  --shadow-xs: 0 1px 2px rgba(28, 25, 23, .05);
  --shadow-sm: 0 1px 2px rgba(28, 25, 23, .04), 0 2px 8px rgba(28, 25, 23, .04);
  --shadow-md: 0 2px 4px rgba(28, 25, 23, .04), 0 12px 32px -8px rgba(28, 25, 23, .12);
  --shadow-lg: 0 24px 64px -12px rgba(28, 25, 23, .28);
  --r-sm: 8px; --r: 12px; --r-lg: 16px; --r-xl: 22px;
  --font: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif;
  --mono: "JetBrains Mono", "D2Coding", ui-monospace, "Cascadia Code", Consolas, monospace;
  --topbar-h: 60px;
  --ease: cubic-bezier(.2, .7, .2, 1);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0c0c0e; --bg-elev: #141417; --bg-sunken: #18181b; --bg-hover: #1f1f23;
    --border: #26262b; --border-strong: #34343a;
    --text: #f4f4f5; --text-2: #d4d4d8; --muted: #a1a1aa; --faint: #71717a;
    --accent: #fb7d3c; --accent-strong: #fdba74; --accent-soft: #24160e; --accent-ring: rgba(251, 125, 60, .28);
    --link: #fdab7c;
    --ok: #4ade80; --ok-soft: #0d1f14; --ok-line: #1f4d2e;
    --warn: #fbbf24; --warn-soft: #221a08; --warn-line: #4a3a10;
    --tip: #7cb2ff; --tip-soft: #0e1729; --tip-line: #1e3a66;
    --bad: #f87171; --bad-soft: #250e0e; --bad-line: #5a1d1d;
    --note-soft: #1d140e; --note-line: #4a2b18;
    --term-bg: #08080a; --term-bar: #121215;
    --shadow-xs: none; --shadow-sm: 0 0 0 1px rgba(255,255,255,.02);
    --shadow-md: 0 12px 32px -8px rgba(0,0,0,.6); --shadow-lg: 0 24px 64px -12px rgba(0,0,0,.8);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0c0c0e; --bg-elev: #141417; --bg-sunken: #18181b; --bg-hover: #1f1f23;
  --border: #26262b; --border-strong: #34343a;
  --text: #f4f4f5; --text-2: #d4d4d8; --muted: #a1a1aa; --faint: #71717a;
  --accent: #fb7d3c; --accent-strong: #fdba74; --accent-soft: #24160e; --accent-ring: rgba(251, 125, 60, .28);
  --link: #fdab7c;
  --ok: #4ade80; --ok-soft: #0d1f14; --ok-line: #1f4d2e;
  --warn: #fbbf24; --warn-soft: #221a08; --warn-line: #4a3a10;
  --tip: #7cb2ff; --tip-soft: #0e1729; --tip-line: #1e3a66;
  --bad: #f87171; --bad-soft: #250e0e; --bad-line: #5a1d1d;
  --note-soft: #1d140e; --note-line: #4a2b18;
  --term-bg: #08080a; --term-bar: #121215;
  --shadow-xs: none; --shadow-sm: 0 0 0 1px rgba(255,255,255,.02);
  --shadow-md: 0 12px 32px -8px rgba(0,0,0,.6); --shadow-lg: 0 24px 64px -12px rgba(0,0,0,.8);
  color-scheme: dark;
}

/* =========================================================
   Base
   ========================================================= */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-padding-top: calc(var(--topbar-h) + 24px); -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: no-preference) { html { scroll-behavior: smooth; } }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 400 16px/1.75 var(--font); letter-spacing: -.011em;
  -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; text-rendering: optimizeLegibility;
}
::selection { background: var(--accent-ring); }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 6px; }
code { font-family: var(--mono); font-size: .86em; background: var(--bg-sunken); border: 1px solid var(--border); padding: .12em .4em; border-radius: 6px; color: var(--text-2); letter-spacing: 0; word-break: break-word; }
kbd { font: 500 11px/1 var(--mono); padding: 3px 6px; border: 1px solid var(--border-strong); border-bottom-width: 2px; border-radius: 5px; background: var(--bg-elev); color: var(--muted); }
small, .muted { color: var(--muted); }
svg { flex-shrink: 0; }
.skip-link { position: absolute; left: 12px; top: -48px; z-index: 100; background: var(--text); color: var(--bg); padding: 8px 14px; border-radius: 8px; }
.skip-link:focus { top: 12px; }

/* =========================================================
   Top bar
   ========================================================= */
.read-progress { position: fixed; inset: 0 0 auto; height: 2px; z-index: 60; pointer-events: none; }
.read-progress span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--accent), #f59e0b); transition: width .1s linear; }
.topbar {
  position: sticky; top: 0; z-index: 40; height: var(--topbar-h);
  display: flex; align-items: center; gap: 16px; padding: 0 24px;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(180%) blur(14px); -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; font-size: 15.5px; letter-spacing: -.02em; min-width: 0; }
.brand:hover { text-decoration: none; }
.brand-mark { width: 28px; height: 28px; border-radius: 8px; display: grid; place-items: center; color: #fff; font-size: 14px; font-weight: 800; background: linear-gradient(135deg, #f97316, #dc2626); box-shadow: 0 2px 8px -2px rgba(234, 88, 12, .6), inset 0 1px 0 rgba(255,255,255,.25); }
.brand-text { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.search-trigger {
  margin-left: 24px; display: flex; align-items: center; gap: 8px; height: 36px; width: min(320px, 32vw); padding: 0 8px 0 12px;
  background: var(--bg-sunken); border: 1px solid var(--border); border-radius: 10px; color: var(--muted); font: 14px var(--font); cursor: pointer; transition: border-color .15s, background .15s;
}
.search-trigger:hover { border-color: var(--border-strong); background: var(--bg-elev); }
.search-trigger span { flex: 1; text-align: left; }
.top-links { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.pill-link { display: inline-flex; align-items: center; gap: 7px; height: 36px; padding: 0 14px; border-radius: 10px; color: var(--text-2); font-size: 14.5px; font-weight: 600; transition: background .15s; }
.pill-link:hover, .pill-link.active { background: var(--bg-hover); color: var(--text); text-decoration: none; }
.icon-btn { display: inline-grid; place-items: center; width: 36px; height: 36px; border-radius: 10px; border: 1px solid transparent; background: none; color: var(--text-2); cursor: pointer; transition: background .15s, color .15s; }
.icon-btn:hover { background: var(--bg-hover); color: var(--text); }
.menu-btn { display: none; margin-left: -8px; }
.theme-btn .i-moon { display: none; }
:root[data-theme="dark"] .theme-btn .i-sun { display: none; }
:root[data-theme="dark"] .theme-btn .i-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-btn .i-sun { display: none; }
  :root:not([data-theme="light"]) .theme-btn .i-moon { display: block; }
}

/* =========================================================
   Layout
   ========================================================= */
.shell { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 48px; max-width: 1380px; margin: 0 auto; padding: 0 32px; }
.shell.has-toc { grid-template-columns: 248px minmax(0, 1fr) 208px; }
.page-post .content { max-width: 780px; width: 100%; justify-self: center; }
.page-home .shell { grid-template-columns: 260px minmax(0, 1fr); }
.content { min-width: 0; padding: 48px 0 96px; }

/* Sidebar */
.sidebar { position: sticky; top: var(--topbar-h); align-self: start; height: calc(100vh - var(--topbar-h)); overflow-y: auto; padding: 28px 4px 48px 0; scrollbar-width: thin; }
.side-link { display: flex; align-items: center; gap: 10px; padding: 8px 12px; border-radius: 10px; color: var(--text-2); font-size: 14.5px; font-weight: 500; margin-bottom: 2px; }
.side-link svg { color: var(--muted); }
.side-link:hover { background: var(--bg-hover); text-decoration: none; color: var(--text); }
.side-link.active { background: var(--bg-elev); color: var(--text); box-shadow: var(--shadow-xs), 0 0 0 1px var(--border); }
.nav-course { margin-top: 26px; }
.nav-course-title { font-size: 11.5px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--faint); padding: 0 12px 8px; }
.nav-course ul { list-style: none; margin: 0; padding: 0; position: relative; }
.nav-course ul::before { content: ""; position: absolute; left: 25px; top: 18px; bottom: 18px; width: 1px; background: var(--border); }
.nav-day { position: relative; display: flex; align-items: center; gap: 12px; padding: 7px 10px; border-radius: 10px; color: var(--text-2); }
.nav-day:hover { background: var(--bg-hover); text-decoration: none; }
.nav-num { position: relative; z-index: 1; width: 30px; height: 30px; flex-shrink: 0; display: grid; place-items: center; border-radius: 50%; font: 700 12.5px var(--font); background: var(--bg-elev); border: 1px solid var(--border-strong); color: var(--text-2); transition: all .15s; }
.nav-day.visited .nav-num { border-color: var(--ok); color: var(--ok); }
.nav-day.active .nav-num { background: var(--accent); border-color: var(--accent); color: #fff; box-shadow: 0 0 0 4px var(--accent-ring); }
.nav-day.pending .nav-num { border-style: dashed; color: var(--faint); background: var(--bg); }
.nav-text { display: flex; flex-direction: column; min-width: 0; line-height: 1.35; }
.nav-title { font-size: 14px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.nav-sub { font-size: 12px; color: var(--muted); }
.nav-day.pending .nav-title { color: var(--muted); font-weight: 500; }
.nav-day.active { background: var(--accent-soft); }
.nav-day.active .nav-title { color: var(--text); }
.nav-empty { padding: 6px 12px; color: var(--faint); font-size: 13px; }
.scrim { display: none; }

/* TOC */
.toc { position: sticky; top: var(--topbar-h); align-self: start; max-height: calc(100vh - var(--topbar-h)); overflow-y: auto; padding: 52px 0 40px; font-size: 13.5px; scrollbar-width: thin; }
.toc-title { font-size: 11.5px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--faint); margin-bottom: 12px; }
.toc ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--border); }
.toc a { display: block; padding: 5px 0 5px 14px; margin-left: -1px; border-left: 2px solid transparent; color: var(--muted); line-height: 1.45; transition: color .15s, border-color .15s; }
.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.active { color: var(--accent); border-left-color: var(--accent); font-weight: 600; }

.footer { border-top: 1px solid var(--border); color: var(--faint); font-size: 13px; text-align: center; padding: 32px 24px 40px; }
.to-top { position: fixed; right: 24px; bottom: 24px; z-index: 30; background: var(--bg-elev); border: 1px solid var(--border); box-shadow: var(--shadow-md); opacity: 0; transform: translateY(8px); pointer-events: none; transition: opacity .2s, transform .2s; }
.to-top.show { opacity: 1; transform: none; pointer-events: auto; }

/* =========================================================
   Home
   ========================================================= */
.hero { position: relative; display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 40px; align-items: center; padding: 44px 44px; border-radius: var(--r-xl); background: var(--bg-elev); border: 1px solid var(--border); box-shadow: var(--shadow-sm); overflow: hidden; isolation: isolate; }
.hero::before { content: ""; position: absolute; inset: -40% -10% auto auto; width: 520px; height: 520px; z-index: -1; background: radial-gradient(closest-side, rgba(249, 115, 22, .16), transparent 70%); }
.hero::after { content: ""; position: absolute; inset: 0; z-index: -1; opacity: .5; background-image: radial-gradient(var(--border) 1px, transparent 1px); background-size: 22px 22px; mask-image: linear-gradient(120deg, transparent 40%, #000 100%); -webkit-mask-image: linear-gradient(120deg, transparent 40%, #000 100%); }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; font-size: 13px; font-weight: 600; color: var(--accent); background: var(--accent-soft); padding: 4px 12px; border-radius: 99px; border: 1px solid var(--note-line); }
.hero h1 { font-size: clamp(30px, 4vw, 44px); line-height: 1.18; letter-spacing: -.035em; margin: 18px 0 14px; font-weight: 800; }
.hero p { color: var(--muted); font-size: 17px; margin: 0; max-width: 520px; }
.hero-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 28px; }
.btn-lg { display: inline-flex; align-items: center; gap: 8px; height: 44px; padding: 0 18px; border-radius: 12px; font-weight: 600; font-size: 15px; color: var(--text); background: var(--bg-elev); border: 1px solid var(--border-strong); box-shadow: var(--shadow-xs); transition: transform .15s var(--ease), box-shadow .15s, border-color .15s; }
.btn-lg:hover { text-decoration: none; transform: translateY(-1px); box-shadow: var(--shadow-sm); }
.btn-lg.primary { background: var(--text); border-color: var(--text); color: var(--bg); }
.resume { margin-top: 18px; font-size: 14px; color: var(--muted); }
.resume a { font-weight: 600; }
.hero-stats { display: flex; flex-direction: column; align-items: center; gap: 22px; padding: 24px; border-radius: var(--r-lg); background: color-mix(in srgb, var(--bg-sunken) 70%, transparent); border: 1px solid var(--border); }
.ring { --p: 0; width: 132px; height: 132px; border-radius: 50%; display: grid; place-items: center; background: conic-gradient(var(--accent) calc(var(--p) * 1%), var(--border) 0); }
.ring > div { width: 108px; height: 108px; border-radius: 50%; background: var(--bg-elev); display: grid; place-content: center; text-align: center; }
.ring b { font-size: 28px; letter-spacing: -.03em; line-height: 1.1; }
.ring span { font-size: 12px; color: var(--muted); }
.hero-stats dl { display: grid; grid-template-columns: repeat(3, 1fr); width: 100%; margin: 0; gap: 8px; }
.hero-stats dl div { text-align: center; }
.hero-stats dt { font-size: 12px; color: var(--muted); }
.hero-stats dd { margin: 2px 0 0; font-size: 22px; font-weight: 800; letter-spacing: -.03em; }
.hero-stats dd small { font-size: 13px; font-weight: 500; }
.course-section { margin-top: 64px; }
.course-head { display: flex; align-items: baseline; gap: 14px; margin-bottom: 20px; flex-wrap: wrap; }
.course-index { font: 700 12px var(--mono); color: var(--accent); letter-spacing: .06em; }
.course-head h2 { margin: 0; font-size: 24px; letter-spacing: -.03em; font-weight: 800; }
.course-count { margin-left: auto; font-size: 13.5px; color: var(--muted); font-weight: 500; }
.day-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; }
.day-card { position: relative; display: flex; flex-direction: column; gap: 10px; padding: 22px 22px 20px; border-radius: var(--r-lg); background: var(--bg-elev); border: 1px solid var(--border); color: var(--text); box-shadow: var(--shadow-xs); transition: transform .2s var(--ease), box-shadow .2s, border-color .2s; }
.day-card:hover { text-decoration: none; transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--border-strong); }
.day-card-top { display: flex; align-items: center; justify-content: space-between; }
.day-badge { font: 700 11.5px var(--mono); letter-spacing: .06em; color: var(--accent); background: var(--accent-soft); border: 1px solid var(--note-line); padding: 3px 9px; border-radius: 7px; }
.day-badge.lg { font-size: 12.5px; padding: 4px 10px; }
.status-chip { font-size: 12px; font-weight: 600; color: var(--muted); display: inline-flex; align-items: center; gap: 6px; }
.status-chip::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--faint); }
.status-chip.done { color: var(--ok); }
.status-chip.done::before { background: var(--ok); box-shadow: 0 0 0 3px var(--ok-soft); }
.day-card-title { font-size: 19px; font-weight: 700; line-height: 1.4; letter-spacing: -.025em; }
.day-card p { margin: 0; color: var(--muted); font-size: 14.5px; line-height: 1.6; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.day-card-meta { display: flex; gap: 14px; flex-wrap: wrap; font-size: 13px; color: var(--muted); margin-top: auto; padding-top: 4px; }
.day-card-meta span, .post-meta span { display: inline-flex; align-items: center; gap: 5px; }
.day-card-go { position: absolute; right: 20px; bottom: 20px; color: var(--faint); transition: transform .2s var(--ease), color .2s; }
.day-card:hover .day-card-go { color: var(--accent); transform: translateX(3px); }
.day-card.is-pending { background: transparent; border-style: dashed; box-shadow: none; }
.day-card.is-pending .day-card-title { color: var(--muted); }
.day-card.is-pending .day-badge { color: var(--muted); background: var(--bg-sunken); border-color: var(--border); }
.day-card.is-pending:hover { transform: none; box-shadow: none; border-color: var(--border-strong); }
.tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tags span { font-size: 12px; font-weight: 500; color: var(--text-2); background: var(--bg-sunken); border: 1px solid var(--border); padding: 2px 9px; border-radius: 99px; }

/* =========================================================
   Post
   ========================================================= */
.post-head { margin-bottom: 32px; }
.crumb { display: flex; gap: 8px; flex-wrap: wrap; font-size: 13.5px; color: var(--muted); margin-bottom: 22px; }
.crumb a { color: var(--muted); }
.crumb span:nth-child(even) { color: var(--faint); }
.post-head h1 { font-size: clamp(30px, 3.6vw, 40px); line-height: 1.22; letter-spacing: -.04em; font-weight: 800; margin: 14px 0 14px; }
.lead { font-size: 18.5px; line-height: 1.65; color: var(--text-2); margin: 0 0 20px; letter-spacing: -.02em; }
.post-meta { display: flex; gap: 18px; flex-wrap: wrap; font-size: 14px; color: var(--muted); margin-bottom: 16px; }
.sources { margin: 0 0 40px; border: 1px solid var(--border); border-radius: var(--r); background: var(--bg-elev); }
.sources summary { list-style: none; display: flex; align-items: center; gap: 10px; padding: 12px 16px; cursor: pointer; font-size: 14px; font-weight: 600; color: var(--text-2); }
.sources summary::-webkit-details-marker { display: none; }
.sources summary::after { content: ""; margin-left: auto; width: 8px; height: 8px; border-right: 2px solid var(--faint); border-bottom: 2px solid var(--faint); transform: rotate(45deg); transition: transform .2s; }
.sources[open] summary::after { transform: rotate(-135deg); }
.sources .count { font-size: 12px; background: var(--bg-sunken); border: 1px solid var(--border); border-radius: 99px; padding: 0 8px; color: var(--muted); }
.sources ul { list-style: none; margin: 0; padding: 4px 16px 8px; border-top: 1px solid var(--border); }
.sources li { display: flex; align-items: center; gap: 10px; padding: 8px 0; font-size: 14px; border-bottom: 1px dashed var(--border); }
.sources li:last-child { border-bottom: 0; }
.file-ext { font: 700 10px var(--mono); width: 36px; text-align: center; padding: 4px 0; border-radius: 6px; background: var(--bg-sunken); border: 1px solid var(--border); color: var(--muted); }
.file-name { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sources p { margin: 0; padding: 10px 16px 14px; font-size: 13px; color: var(--muted); border-top: 1px solid var(--border); }

.post { font-size: 16.5px; color: var(--text-2); }
.post > * + * { margin-top: 0; }
.post p { margin: 0 0 1.15em; word-break: keep-all; overflow-wrap: anywhere; }
.post li { word-break: keep-all; overflow-wrap: anywhere; }
.post strong { color: var(--text); font-weight: 700; }
.post h2, .post h3, .post h4 { color: var(--text); position: relative; letter-spacing: -.03em; word-break: keep-all; }
.post h2 { font-size: 27px; line-height: 1.3; font-weight: 800; margin: 72px 0 20px; padding-top: 28px; border-top: 1px solid var(--border); }
.post > h2:first-child { margin-top: 24px; }
.post h3 { font-size: 20px; line-height: 1.4; font-weight: 700; margin: 40px 0 12px; }
.post h4 { font-size: 17px; margin: 28px 0 8px; }
.anchor { position: absolute; left: -26px; top: auto; width: 20px; color: var(--faint); opacity: 0; font-weight: 500; transition: opacity .15s; }
.post h2 .anchor { top: 28px; }
.post h2:hover .anchor, .post h3:hover .anchor { opacity: 1; text-decoration: none; }
.post ul, .post ol { padding-left: 1.4em; margin: 0 0 1.2em; }
.post li { margin: .35em 0; }
.post li::marker { color: var(--faint); }
.post ol li::marker { color: var(--accent); font-weight: 700; font-size: .92em; }
.post hr { border: 0; height: 0; margin: 48px 0 0; }
.post img { max-width: 100%; border-radius: var(--r); border: 1px solid var(--border); }
.post details:not(.sources) { margin: 16px 0 24px; border: 1px solid var(--border); border-radius: var(--r); padding: 0 18px; background: var(--bg-elev); }
.post details:not(.sources) summary { cursor: pointer; padding: 12px 0; font-weight: 600; color: var(--text); }
.post details[open]:not(.sources) { padding-bottom: 6px; }

/* Tables */
.table-wrap { margin: 20px 0 28px; overflow-x: auto; border: 1px solid var(--border); border-radius: var(--r); background: var(--bg-elev); box-shadow: var(--shadow-xs); scrollbar-width: thin; }
.post table { width: 100%; border-collapse: collapse; font-size: 14.5px; line-height: 1.6; }
.post th, .post td { padding: 11px 16px; text-align: left; vertical-align: top; border-bottom: 1px solid var(--border); }
.post th { background: var(--bg-sunken); color: var(--text); font-weight: 700; font-size: 13px; white-space: nowrap; letter-spacing: -.01em; }
.post td { word-break: keep-all; }
.post td:first-child { color: var(--text); font-weight: 600; }
.post tbody tr:last-child td { border-bottom: 0; }
.post tbody tr:hover td { background: color-mix(in srgb, var(--bg-sunken) 55%, transparent); }

/* Callouts */
.callout { display: flex; gap: 12px; margin: 22px 0 26px; padding: 14px 18px; border-radius: var(--r); border: 1px solid var(--note-line); background: var(--note-soft); color: var(--text-2); font-size: 15.5px; }
.callout > div { min-width: 0; flex: 1; }
.callout p { margin: 4px 0; }
.callout-icon { width: 22px; height: 22px; flex-shrink: 0; margin-top: 3px; border-radius: 6px; display: grid; place-items: center; font-size: 12px; font-weight: 800; color: #fff; background: var(--accent); }
.callout-icon::before { content: "i"; font-family: Georgia, serif; font-style: italic; }
.callout.warn { background: var(--warn-soft); border-color: var(--warn-line); }
.callout.warn .callout-icon { background: var(--warn); } .callout.warn .callout-icon::before { content: "!"; font-family: var(--font); font-style: normal; }
.callout.tip { background: var(--tip-soft); border-color: var(--tip-line); }
.callout.tip .callout-icon { background: var(--tip); } .callout.tip .callout-icon::before { content: "★"; font-style: normal; font-size: 11px; }
.callout.key { background: var(--ok-soft); border-color: var(--ok-line); }
.callout.key .callout-icon { background: var(--ok); } .callout.key .callout-icon::before { content: "✓"; font-style: normal; font-family: var(--font); }

/* Task list */
li.task { list-style: none; margin-left: -1.4em; }
li.task label { display: flex; gap: 12px; align-items: flex-start; padding: 10px 14px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg-elev); cursor: pointer; transition: border-color .15s, background .15s; }
li.task label:hover { border-color: var(--border-strong); }
li.task input { appearance: none; -webkit-appearance: none; flex-shrink: 0; width: 20px; height: 20px; margin: 3px 0 0; border-radius: 6px; border: 1.5px solid var(--border-strong); background: var(--bg); display: grid; place-items: center; cursor: pointer; transition: all .15s; }
li.task input::after { content: ""; width: 5px; height: 10px; border: solid #fff; border-width: 0 2px 2px 0; transform: rotate(45deg) translate(-1px, -1px) scale(0); transition: transform .15s var(--ease); }
li.task input:checked { background: var(--ok); border-color: var(--ok); }
li.task input:checked::after { transform: rotate(45deg) translate(-1px, -1px) scale(1); }
li.task input:checked + span { color: var(--muted); text-decoration: line-through; text-decoration-color: var(--faint); }
li.task:has(input:checked) label { background: var(--ok-soft); border-color: var(--ok-line); }

/* Code */
.code-block { margin: 18px 0 26px; border: 1px solid var(--border); border-radius: var(--r); background: var(--bg-elev); overflow: hidden; box-shadow: var(--shadow-xs); }
.code-head { display: flex; align-items: center; justify-content: space-between; padding: 6px 8px 6px 16px; border-bottom: 1px solid var(--border); background: var(--bg-sunken); }
.code-lang { font: 600 11.5px var(--mono); color: var(--muted); text-transform: lowercase; }
.copy-btn { font: 500 12px var(--font); color: var(--muted); background: transparent; border: 1px solid transparent; border-radius: 7px; padding: 3px 10px; cursor: pointer; transition: all .15s; }
.copy-btn:hover { background: var(--bg-elev); border-color: var(--border); color: var(--text); }
.copy-btn.copied { color: var(--ok); }
.code-block pre { margin: 0; padding: 16px 18px; overflow-x: auto; font: 13.5px/1.7 var(--mono); letter-spacing: 0; scrollbar-width: thin; }
.code-block code { background: none; border: 0; padding: 0; font-size: inherit; color: var(--text); }

/* Empty / pager */
.empty-state { text-align: center; padding: 48px 24px; margin-bottom: 32px; border: 1px dashed var(--border-strong); border-radius: var(--r-lg); background: var(--bg-elev); }
.empty-icon { font-size: 40px; margin-bottom: 8px; }
.empty-state p { margin: 6px 0; }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 80px; padding-top: 32px; border-top: 1px solid var(--border); }
.pager a { display: flex; flex-direction: column; gap: 2px; padding: 16px 20px; border-radius: var(--r); border: 1px solid var(--border); background: var(--bg-elev); color: var(--text); font-weight: 600; transition: border-color .15s, box-shadow .15s; }
.pager a:hover { text-decoration: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-ring); }
.pager small { font-size: 12.5px; font-weight: 500; }
.pager .prev small::before { content: "← "; }
.pager .next { text-align: right; grid-column: 2; }
.pager .next small::after { content: " →"; }

/* =========================================================
   Search modal
   ========================================================= */
.search-modal { position: fixed; inset: 0; z-index: 80; display: flex; justify-content: center; align-items: flex-start; padding: 12vh 16px 16px; background: rgba(12, 10, 9, .45); backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px); animation: fade .15s ease; }
.search-modal[hidden] { display: none; }
.search-box { width: min(640px, 100%); max-height: 70vh; display: flex; flex-direction: column; background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--r-lg); box-shadow: var(--shadow-lg); overflow: hidden; animation: pop .18s var(--ease); }
.search-input-row { display: flex; align-items: center; gap: 12px; padding: 0 16px; border-bottom: 1px solid var(--border); color: var(--muted); }
.search-input-row input { flex: 1; height: 56px; border: 0; outline: 0; background: none; color: var(--text); font: 17px var(--font); }
.search-input-row input::-webkit-search-cancel-button { display: none; }
.search-results { list-style: none; margin: 0; padding: 8px; overflow-y: auto; }
.search-results li a { display: flex; align-items: center; gap: 12px; padding: 10px 12px; border-radius: 10px; color: var(--text); }
.search-results li a:hover, .search-results li.sel a { background: var(--accent-soft); text-decoration: none; }
.search-results .k { width: 28px; height: 28px; flex-shrink: 0; border-radius: 8px; display: grid; place-items: center; background: var(--bg-sunken); border: 1px solid var(--border); font-size: 12px; color: var(--muted); }
.search-results .t { font-weight: 600; font-size: 14.5px; display: block; }
.search-results .s { font-size: 12.5px; color: var(--muted); display: block; }
.search-results mark { background: none; color: var(--accent); }
.search-results .empty { padding: 28px; text-align: center; color: var(--muted); font-size: 14px; }
.search-foot { display: flex; gap: 16px; padding: 10px 16px; border-top: 1px solid var(--border); font-size: 12px; color: var(--muted); background: var(--bg-sunken); }
.search-foot kbd { margin-right: 3px; }
@keyframes fade { from { opacity: 0; } }
@keyframes pop { from { opacity: 0; transform: translateY(-8px) scale(.98); } }

/* =========================================================
   Practice widgets
   ========================================================= */
.practice { margin: 32px 0 36px; border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--bg-elev); box-shadow: var(--shadow-sm); overflow: hidden; color: var(--text); font-size: 15px; }
.practice-head { display: flex; align-items: center; gap: 12px; padding: 12px 16px; border-bottom: 1px solid var(--border); flex-wrap: wrap; }
.practice-icon { width: 34px; height: 34px; border-radius: 10px; display: grid; place-items: center; font-size: 17px; background: var(--accent-soft); border: 1px solid var(--note-line); flex-shrink: 0; }
.practice-titles { display: flex; flex-direction: column; line-height: 1.35; min-width: 0; }
.practice-badge { font-size: 11.5px; font-weight: 700; color: var(--accent); letter-spacing: .02em; }
.practice-title { font-weight: 700; font-size: 15px; color: var(--text); }
.practice-actions { margin-left: auto; display: flex; gap: 6px; }
.practice-body { padding: 18px; }
.btn { display: inline-flex; align-items: center; gap: 6px; height: 34px; padding: 0 14px; border-radius: 9px; border: 1px solid var(--border-strong); background: var(--bg-elev); color: var(--text); font: 600 13.5px var(--font); cursor: pointer; transition: all .15s; }
.btn:hover { background: var(--bg-hover); }
.btn:disabled { opacity: .55; cursor: progress; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; box-shadow: 0 1px 2px rgba(234,88,12,.3), inset 0 1px 0 rgba(255,255,255,.15); }
.btn.primary:hover { background: var(--accent-strong); border-color: var(--accent-strong); }
.btn.small { height: 30px; padding: 0 11px; font-size: 12.5px; border-radius: 8px; }
textarea.editor { display: block; width: 100%; min-height: 190px; resize: vertical; font: 13.5px/1.7 var(--mono); letter-spacing: 0; padding: 14px 16px; border: 1px solid var(--border); border-radius: var(--r); background: var(--bg); color: var(--text); tab-size: 2; transition: border-color .15s, box-shadow .15s; }
textarea.editor:focus { outline: 0; border-color: var(--accent); box-shadow: 0 0 0 4px var(--accent-ring); }

/* Terminal */
.term-window { background: var(--term-bg); }
.term-chrome { display: flex; align-items: center; gap: 8px; padding: 10px 14px; background: var(--term-bar); border-bottom: 1px solid rgba(255,255,255,.06); }
.term-chrome i { width: 11px; height: 11px; border-radius: 50%; background: #ff5f57; }
.term-chrome i:nth-child(2) { background: #febc2e; } .term-chrome i:nth-child(3) { background: #28c840; }
.term-chrome span { flex: 1; text-align: center; font: 12px var(--mono); color: #8b8b93; margin-right: 50px; }
.term { background: var(--term-bg); color: var(--term-text); font: 13.5px/1.65 var(--mono); letter-spacing: 0; height: 420px; overflow-y: auto; padding: 16px 18px; cursor: text; scrollbar-width: thin; scrollbar-color: #333 transparent; }
.term .line { white-space: pre-wrap; word-break: break-word; }
.term .in-row { display: flex; gap: 8px; }
.term .in-row input { flex: 1; min-width: 0; background: none; border: 0; outline: 0; color: #fafafa; font: inherit; padding: 0; caret-color: #fb923c; }
.term .ps { color: #4ade80; white-space: nowrap; }
.term .ps.claude { color: #fb923c; }
.term .c-dim { color: #8b8b93; } .term .c-ok { color: #4ade80; } .term .c-err { color: #f87171; } .term .c-acc { color: #fb923c; }
.term .c-blue { color: #7cb2ff; } .term .c-bold { font-weight: 700; color: #fff; }
.term-status { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding: 7px 18px; background: var(--term-bar); color: #8b8b93; font: 12px var(--mono); border-top: 1px solid rgba(255,255,255,.06); }
.term-status .mode { color: #fb923c; font-weight: 600; }
.term-hints { display: flex; gap: 6px; overflow-x: auto; padding: 12px 16px; border-top: 1px solid var(--border); background: var(--bg-elev); scrollbar-width: thin; }
.term-hints .btn { flex-shrink: 0; font: 500 12px var(--mono); letter-spacing: 0; height: 28px; }
.term-hints .hint-label { flex-shrink: 0; align-self: center; font-size: 12px; color: var(--muted); font-weight: 600; margin-right: 4px; }
.term-missions { padding: 16px 18px; border-top: 1px solid var(--border); background: var(--bg-sunken); }
.missions-head { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; font-weight: 700; font-size: 14px; }
.missions-head .bar { flex: 1; max-width: 200px; height: 6px; border-radius: 99px; background: var(--border); overflow: hidden; }
.missions-head .bar span { display: block; height: 100%; background: var(--ok); border-radius: 99px; transition: width .4s var(--ease); }
.missions-head .done-msg { color: var(--ok); font-size: 13px; }
.term-missions ol { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; counter-reset: m; }
.term-missions li { counter-increment: m; display: flex; gap: 10px; align-items: flex-start; font-size: 14px; color: var(--text-2); line-height: 1.55; }
.term-missions li::before { content: counter(m); flex-shrink: 0; width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center; font: 700 11px var(--font); border: 1.5px solid var(--border-strong); color: var(--muted); background: var(--bg-elev); margin-top: 1px; }
.term-missions li.done { color: var(--muted); text-decoration: line-through; text-decoration-color: var(--faint); }
.term-missions li.done::before { content: "✓"; background: var(--ok); border-color: var(--ok); color: #fff; }
.term-missions li.current { color: var(--text); font-weight: 600; }
.term-missions li.current::before { border-color: var(--accent); color: var(--accent); box-shadow: 0 0 0 3px var(--accent-ring); }
.term-editor { border-top: 1px solid var(--border); }

/* Checkers */
.checks { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 8px; margin-top: 14px; }
.check { display: flex; gap: 10px; align-items: flex-start; padding: 10px 12px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg); transition: all .2s; }
.check::before { content: ""; flex-shrink: 0; width: 18px; height: 18px; margin-top: 2px; border-radius: 50%; border: 1.5px dashed var(--border-strong); }
.check.ok { border-color: var(--ok-line); background: var(--ok-soft); }
.check.ok::before { content: "✓"; border: 0; background: var(--ok); color: #fff; display: grid; place-items: center; font-size: 11px; font-weight: 800; }
.check b { display: block; font-size: 13.5px; color: var(--text); }
.check span { display: block; font-size: 12.5px; color: var(--muted); line-height: 1.5; }
.check.bonus b::after { content: "보너스"; margin-left: 6px; font-size: 10.5px; font-weight: 700; color: var(--tip); background: var(--tip-soft); border: 1px solid var(--tip-line); padding: 0 6px; border-radius: 99px; vertical-align: 1px; }
.score { display: flex; align-items: center; gap: 14px; margin-top: 16px; }
.score-num { font-size: 24px; font-weight: 800; letter-spacing: -.03em; }
.score-num small { font-size: 14px; font-weight: 500; }
.score .bar { flex: 1; height: 8px; border-radius: 99px; background: var(--bg-sunken); border: 1px solid var(--border); overflow: hidden; }
.score .bar span { display: block; height: 100%; background: linear-gradient(90deg, var(--accent), var(--ok)); border-radius: 99px; transition: width .4s var(--ease); }
.score-msg { font-size: 13.5px; color: var(--muted); }
.inline-warn { margin-top: 12px; padding: 10px 14px; border-radius: 10px; font-size: 13.5px; background: var(--warn-soft); border: 1px solid var(--warn-line); color: var(--text-2); }
.row { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin-top: 12px; }

/* Web / Python */
.seg { display: inline-flex; padding: 3px; gap: 2px; border-radius: 10px; background: var(--bg-sunken); border: 1px solid var(--border); margin-bottom: 10px; }
.seg button { border: 0; background: none; padding: 5px 14px; border-radius: 7px; cursor: pointer; color: var(--muted); font: 600 12.5px var(--mono); }
.seg button.active { background: var(--bg-elev); color: var(--text); box-shadow: var(--shadow-xs), 0 0 0 1px var(--border); }
.web-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.web-grid textarea.editor { min-height: 300px; }
.preview-label { font-size: 12px; font-weight: 600; color: var(--muted); margin: 6px 0 12px; display: flex; align-items: center; gap: 6px; }
.preview-label::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--ok); }
.web-preview { width: 100%; height: 300px; border: 1px solid var(--border); border-radius: var(--r); background: #fff; }
.py-out { margin-top: 12px; padding: 14px 16px; min-height: 84px; max-height: 340px; overflow: auto; border-radius: var(--r); background: var(--term-bg); color: var(--term-text); font: 13px/1.7 var(--mono); letter-spacing: 0; white-space: pre-wrap; }
.py-out .err { color: #f87171; }
.py-out:empty { display: none; }

/* Quiz */
.quiz-progress { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; font-size: 13px; color: var(--muted); font-weight: 600; }
.quiz-progress .bar { flex: 1; height: 6px; border-radius: 99px; background: var(--bg-sunken); overflow: hidden; }
.quiz-progress .bar span { display: block; height: 100%; background: var(--accent); transition: width .3s var(--ease); }
.quiz-q { padding: 18px 0; border-top: 1px solid var(--border); }
.quiz-q:first-of-type { border-top: 0; padding-top: 0; }
.quiz-q > b { display: flex; gap: 10px; font-size: 15.5px; margin-bottom: 12px; color: var(--text); line-height: 1.5; }
.quiz-q > b em { font-style: normal; color: var(--accent); font-family: var(--mono); font-size: 13px; padding-top: 2px; }
.quiz-opts { display: grid; gap: 8px; }
.quiz-opt { display: flex; align-items: center; gap: 12px; width: 100%; text-align: left; padding: 11px 14px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg); color: var(--text); font: 500 14.5px var(--font); cursor: pointer; transition: all .15s; }
.quiz-opt .letter { flex-shrink: 0; width: 24px; height: 24px; border-radius: 7px; display: grid; place-items: center; font: 700 12px var(--mono); background: var(--bg-sunken); border: 1px solid var(--border); color: var(--muted); }
.quiz-opt:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-soft); }
.quiz-opt:disabled { cursor: default; }
.quiz-opt.right { border-color: var(--ok); background: var(--ok-soft); }
.quiz-opt.right .letter { background: var(--ok); border-color: var(--ok); color: #fff; }
.quiz-opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.quiz-opt.wrong .letter { background: var(--bad); border-color: var(--bad); color: #fff; }
.quiz-opt.dim { opacity: .55; }
.quiz-exp { margin-top: 10px; padding: 10px 14px; border-radius: 10px; font-size: 14px; color: var(--text-2); background: var(--tip-soft); border: 1px solid var(--tip-line); }
.quiz-total { margin-top: 18px; padding: 16px; border-radius: var(--r); text-align: center; font-weight: 700; background: var(--bg-sunken); border: 1px solid var(--border); }
.quiz-total:empty { display: none; }

/* Playground page */
.pg-head { margin-bottom: 24px; }
.pg-head h1 { font-size: clamp(28px, 3.4vw, 38px); letter-spacing: -.04em; font-weight: 800; margin: 12px 0 10px; }
.pg-tabs { display: flex; gap: 4px; padding: 4px; margin: 8px 0 24px; border-radius: 14px; background: var(--bg-sunken); border: 1px solid var(--border); overflow-x: auto; scrollbar-width: none; }
.pg-tabs button { flex: 1 0 auto; display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 9px 16px; border: 0; border-radius: 10px; background: none; color: var(--muted); font: 600 14px var(--font); cursor: pointer; white-space: nowrap; transition: all .15s; }
.pg-tabs button:hover { color: var(--text); }
.pg-tabs button.active { background: var(--bg-elev); color: var(--text); box-shadow: var(--shadow-sm), 0 0 0 1px var(--border); }
.pg-intro { color: var(--muted); margin: 0 0 4px; font-size: 15px; }
.pg-panel[hidden] { display: none; }
.pg-panel .practice { margin-top: 16px; }
.page-playground .shell { grid-template-columns: 260px minmax(0, 1fr); }
.page-playground .content { max-width: 1040px; }

/* =========================================================
   Responsive
   ========================================================= */
@media (max-width: 1240px) {
  .shell.has-toc { grid-template-columns: 252px minmax(0, 1fr); gap: 48px; }
  .toc { display: none; }
}
@media (max-width: 960px) {
  :root { --topbar-h: 56px; }
  .menu-btn { display: inline-grid; }
  .topbar { padding: 0 16px; gap: 10px; }
  .search-trigger { margin-left: auto; width: 36px; padding: 0; justify-content: center; border-radius: 10px; }
  .search-trigger span, .search-trigger kbd { display: none; }
  .top-links { margin-left: 0; }
  .pill-link span { display: none; }
  .pill-link { width: 36px; padding: 0; justify-content: center; }
  .shell, .shell.has-toc, .page-home .shell, .page-playground .shell { grid-template-columns: minmax(0, 1fr); padding: 0 16px; gap: 0; }
  .sidebar { position: fixed; z-index: 50; top: 0; left: 0; bottom: 0; height: 100%; width: min(320px, 86vw); padding: 20px 14px 40px; background: var(--bg); border-right: 1px solid var(--border); transform: translateX(-102%); transition: transform .28s var(--ease); box-shadow: var(--shadow-lg); }
  body.nav-open .sidebar { transform: none; }
  .scrim { display: block; position: fixed; inset: 0; z-index: 45; background: rgba(12, 10, 9, .4); opacity: 0; pointer-events: none; transition: opacity .25s; }
  body.nav-open .scrim { opacity: 1; pointer-events: auto; }
  body.nav-open { overflow: hidden; }
  .content { padding: 28px 0 64px; }
  .hero { grid-template-columns: 1fr; padding: 28px 22px; gap: 28px; border-radius: var(--r-lg); }
  .hero-stats { flex-direction: row; padding: 18px; }
  .ring { width: 104px; height: 104px; } .ring > div { width: 84px; height: 84px; } .ring b { font-size: 22px; }
  .hero-stats dl { grid-template-columns: 1fr; text-align: left; }
  .hero-stats dl div { display: flex; justify-content: space-between; align-items: baseline; text-align: left; gap: 12px; }
  .hero-stats dd { font-size: 18px; }
  .day-grid { grid-template-columns: 1fr; }
  .post { font-size: 16px; }
  .post h2 { font-size: 23px; margin-top: 56px; }
  .anchor { display: none; }
  .web-grid { grid-template-columns: 1fr; }
  .term { height: 360px; font-size: 12.5px; padding: 14px; }
  .pager { grid-template-columns: 1fr; }
  .pager .next { grid-column: auto; }
  .to-top { right: 16px; bottom: 16px; }
  .search-modal { padding-top: 8vh; }
}
@media (max-width: 480px) {
  .brand-text { font-size: 14.5px; }
  .hero-actions .btn-lg { flex: 1; justify-content: center; }
  .practice-body { padding: 14px; }
  .practice-head { padding: 12px; }
  .checks { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation: none !important; transition: none !important; } }
@media print {
  .topbar, .sidebar, .toc, .to-top, .pager, .practice, .read-progress, .footer { display: none !important; }
  .shell { display: block; }
}