/* ============================================================
   Signal Vol.3 — 디지털 인터랙티브 매거진 공통 스타일
   theme: "루프 엔지니어링(2026) — 에이전틱 루프 편"
   시리즈: 빌린다(Vol.1) → 들인다(Vol.2) → 스스로 돌게 한다(Vol.3)
   자급자족(외부 빌드·CDN 0). 색 대비 WCAG AA 이상 목표.
   Vol.2 브랜드 톤 계승 + 루프 모티프(생각→도구→관찰→다시).
   ============================================================ */

:root {
  --bg:        #f7f6f2;
  --surface:   #ffffff;
  --surface-2: #f0eee7;
  --ink:       #171622;
  --ink-soft:  #383747;
  --muted:     #5d5c70;
  --border:    #e4e1d7;

  --accent:    #4b34d6;   /* electric indigo — Signal identity (Vol.1~3 공통) */
  --accent-ink:#3a27ad;
  --accent-bg: #ece7ff;
  --signal:    #e8451f;   /* signal orange */
  --signal-bg: #ffe8df;

  /* 루프 4박자 팔레트 (위젯 내부 색과 정렬: 생각·도구·관찰) */
  --think:     #7c5cff;   /* 💭 생각 */
  --think-bg:  #efeaff;
  --act:       #2f6fff;   /* 🔧 도구 */
  --act-bg:    #e5eeff;
  --observe:   #1c9e6f;   /* 👁 관찰 */
  --observe-bg:#e0f4ec;
  --loop:      #e8871e;   /* 🔁 다시(되먹임·토큰 누적) */
  --loop-bg:   #fbeecf;

  --ok:        #1f7a4d;
  --ok-bg:     #e2f3ea;
  --warn:      #9a6b00;
  --warn-bg:   #fbf0d6;
  --danger:    #c0392b;
  --danger-bg: #fbe4e0;

  --code-bg:   #1c1b2a;
  --code-ink:  #e6e6f0;
  --radius:    14px;
  --radius-sm: 9px;
  --shadow:    0 1px 2px rgba(20,20,40,.05), 0 8px 24px rgba(20,20,40,.06);
  --shadow-lg: 0 10px 40px rgba(30,20,80,.14);
  --maxtext:   740px;
  --font: "Pretendard", "Apple SD Gothic Neo", "Noto Sans KR", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", "SFMono-Regular", "Consolas", "D2Coding", ui-monospace, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; font-family: var(--font); background: var(--bg); color: var(--ink);
  line-height: 1.72; font-size: 18px;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
img { max-width: 100%; height: auto; }
a { color: var(--accent-ink); text-decoration-thickness: 1.5px; text-underline-offset: 3px; }
a:hover { color: var(--accent); }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--accent); color: #fff; padding: 10px 16px; z-index: 100; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ---------- reading progress bar ---------- */
.progress-rail { position: fixed; inset: 0 0 auto 0; height: 4px; background: transparent; z-index: 50; }
.progress-fill { height: 100%; width: 0; background: linear-gradient(90deg, var(--think), var(--act), var(--observe), var(--loop)); transition: width .1s linear; }

/* ---------- masthead ---------- */
.masthead {
  border-bottom: 1px solid var(--border); background: var(--surface);
  position: sticky; top: 0; z-index: 40; backdrop-filter: saturate(1.2) blur(6px);
}
.masthead-inner { max-width: 1080px; margin: 0 auto; padding: 14px 22px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { font-weight: 800; letter-spacing: .14em; font-size: 20px; color: var(--ink); text-decoration: none; display: inline-flex; align-items: center; gap: 10px; }
.brand .dot { color: var(--signal); }
.brand small { font-weight: 600; letter-spacing: .04em; color: var(--muted); font-size: 12px; }
.masthead nav { display: flex; gap: 16px; font-size: 14px; }
.masthead nav a { text-decoration: none; color: var(--muted); font-weight: 600; }
.masthead nav a:hover { color: var(--accent); }

/* ============================================================ COVER ============================================================ */
.cover { max-width: 1080px; margin: 0 auto; padding: 56px 22px 24px; }
.cover-kicker { display: inline-block; font-weight: 700; letter-spacing: .12em; color: var(--signal); background: var(--signal-bg); padding: 6px 14px; border-radius: 999px; font-size: 13px; margin-bottom: 22px; }
.cover h1 { font-size: clamp(34px, 6vw, 62px); line-height: 1.07; margin: 0 0 18px; letter-spacing: -.02em; font-weight: 800; }
.cover h1 .grad { background: linear-gradient(100deg, var(--think), var(--act) 45%, var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.cover-lede { font-size: clamp(17px, 2.3vw, 21px); color: var(--ink-soft); max-width: 800px; margin: 0 0 22px; }
.cover-lede strong { color: var(--ink); }
.cover-promise { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px 22px; max-width: 860px; box-shadow: var(--shadow); font-size: 16px; color: var(--ink-soft); }
.cover-promise strong { color: var(--ink); }

/* 시리즈 이동(빌린다→들인다→스스로 돌게) */
.cover-move { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin: 20px 0 6px; font-weight: 700; color: var(--muted); font-size: 15px; }
.cover-move .from { color: var(--muted); background: var(--surface-2); padding: 6px 14px; border-radius: 999px; border: 1px solid var(--border); }
.cover-move .arrow { color: var(--signal); font-size: 18px; }
.cover-move .to { color: #fff; background: linear-gradient(100deg, var(--accent), var(--accent-ink)); padding: 6px 14px; border-radius: 999px; }

/* 루프 모티프 스트립 (생각→도구→관찰→다시) */
.loop-strip { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin: 26px 0 6px; }
.loop-strip .beat { display: inline-flex; align-items: center; gap: 7px; font-weight: 700; font-size: 14.5px; padding: 8px 14px; border-radius: 999px; border: 1.5px solid; background: var(--surface); }
.loop-strip .beat.think   { color: var(--think);   border-color: var(--think);   background: var(--think-bg); }
.loop-strip .beat.act     { color: var(--act);     border-color: var(--act);     background: var(--act-bg); }
.loop-strip .beat.observe { color: var(--observe); border-color: var(--observe); background: var(--observe-bg); }
.loop-strip .beat.again   { color: var(--loop);    border-color: var(--loop);    background: var(--loop-bg); }
.loop-strip .to-next { color: var(--muted); font-weight: 800; font-size: 17px; }
.loop-strip .to-loop { color: var(--loop); font-weight: 800; font-size: 15px; align-self: center; }

/* ============================================================ TOC ============================================================ */
.toc { max-width: 1080px; margin: 0 auto; padding: 28px 22px 80px; }
.toc-head { display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 12px; margin-bottom: 18px; }
.toc-head h2 { font-size: 22px; margin: 0; }
.toc-head .count { color: var(--muted); font-size: 14px; }
.filters { display: flex; gap: 8px; flex-wrap: wrap; margin: 4px 0 10px; align-items: center; }
.filters .flabel { font-size: 13px; font-weight: 700; color: var(--muted); margin-right: 4px; }
.filter-chip { font: inherit; font-size: 14px; font-weight: 600; border: 1.5px solid var(--border); background: var(--surface); color: var(--ink-soft); padding: 8px 16px; border-radius: 999px; cursor: pointer; transition: all .15s; }
.filter-chip:hover { border-color: var(--accent); color: var(--accent); }
.filter-chip[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: #fff; }
.filter-note { font-size: 13px; color: var(--muted); margin: 0 0 24px; }

.card-grid { display: grid; gap: 18px; grid-template-columns: repeat(auto-fill, minmax(330px, 1fr)); }
.card { position: relative; display: flex; flex-direction: column; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); transition: transform .15s, box-shadow .15s, border-color .15s; cursor: pointer; }
.card.is-hidden { display: none; }
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); border-color: var(--accent); }
.card-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
.card-no { font-weight: 800; font-size: 13px; color: var(--accent); background: var(--accent-bg); width: 30px; height: 30px; border-radius: 8px; display: grid; place-items: center; }
.status-pill { font-size: 12px; font-weight: 700; padding: 4px 11px; border-radius: 999px; }
.status-live { color: #fff; background: var(--observe); }
.card h3 { font-size: 19px; margin: 2px 0 6px; line-height: 1.3; }
.card h3 a { color: var(--ink); text-decoration: none; }
.card:hover h3 a { color: var(--accent-ink); }
.card-hook { font-size: 14.5px; color: var(--muted); margin: 0 0 16px; flex: 1; }
.card-hook strong { color: var(--ink-soft); }
.card .cover-tag { position: absolute; top: -10px; right: 16px; font-size: 11px; font-weight: 800; letter-spacing: .06em; color: #fff; background: linear-gradient(100deg, var(--accent), var(--signal)); padding: 4px 12px; border-radius: 999px; box-shadow: var(--shadow); }

.badges { display: flex; flex-wrap: wrap; gap: 7px; }
.badge { font-size: 12px; font-weight: 700; padding: 4px 10px; border-radius: 7px; display: inline-flex; align-items: center; gap: 5px; white-space: nowrap; }
.b-diff-1 { color: var(--ok);     background: var(--ok-bg); }
.b-diff-2 { color: #9a6b00;       background: #fbf0d6; }
.b-diff-3 { color: #b03a6e;       background: #f8e2ef; }
.b-mode-make { color: var(--accent-ink); background: var(--accent-bg); }
.b-mode-run  { color: #0d6a6a;    background: #d9f1f1; }
.b-mode-feel { color: #b8456b;    background: #fbe4ec; }
.b-time      { color: var(--muted); background: var(--surface-2); }
.b-sense     { color: var(--loop); background: var(--loop-bg); }
.toc-foot { margin-top: 40px; padding-top: 22px; border-top: 1px dashed var(--border); color: var(--muted); font-size: 14px; }
.toc-foot strong { color: var(--ink-soft); }

/* ============================================================ ARTICLE ============================================================ */
.article { max-width: var(--maxtext); margin: 0 auto; padding: 40px 22px 30px; }
.article-header { margin-bottom: 8px; }
.crumbs { font-size: 14px; margin-bottom: 18px; }
.crumbs a { color: var(--muted); text-decoration: none; }
.crumbs a:hover { color: var(--accent); }
.article h1 { font-size: clamp(28px, 5vw, 40px); line-height: 1.18; margin: 6px 0 10px; letter-spacing: -.01em; font-weight: 800; }
.article .subtitle { font-size: 19px; color: var(--muted); margin: 0 0 18px; line-height: 1.5; }
.article-meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 8px; }
.byline { color: var(--muted); font-size: 14px; margin: 22px 0 0; padding-top: 16px; border-top: 1px solid var(--border); }

.article-body { font-size: 18px; }
.article-body > p { margin: 1.15em 0; color: var(--ink-soft); }
.article-body h2 { font-size: 25px; margin: 1.9em 0 .5em; line-height: 1.3; letter-spacing: -.01em; padding-top: 6px; }
.article-body h2::before { content: ""; display: block; width: 42px; height: 4px; border-radius: 3px; background: linear-gradient(90deg, var(--think), var(--act), var(--observe)); margin-bottom: 14px; }
.article-body h3 { font-size: 20px; margin: 1.5em 0 .4em; }
.article-body ul, .article-body ol { padding-left: 1.2em; color: var(--ink-soft); }
.article-body li { margin: .5em 0; }
.article-body strong { color: var(--ink); }
.article-body blockquote { margin: 1.2em 0; padding: 4px 0 4px 18px; border-left: 4px solid var(--accent-bg); color: var(--ink-soft); font-style: italic; }
.article-body blockquote em { color: var(--accent-ink); font-style: normal; }
.article-body em { color: var(--ink-soft); }

/* 목표 배너 (에이전트에게 던지는 목표 한 줄) */
.goal-line { font-family: var(--mono); font-size: 15px; background: linear-gradient(90deg,#111827,#374151); color: #fff; padding: 14px 16px 14px 44px; border-radius: var(--radius-sm); margin: 1.2em 0; position: relative; word-break: break-word; }
.goal-line::before { content: "🎯"; position: absolute; left: 14px; top: 13px; font-size: 18px; }

/* data table in body */
.article-body .data-table { width: 100%; border-collapse: collapse; margin: 1.3em 0; font-size: 15px; }
.article-body .data-table th, .article-body .data-table td { border: 1px solid var(--border); padding: 9px 12px; text-align: left; }
.article-body .data-table thead th { background: var(--surface-2); font-weight: 700; }
.article-body .data-table tbody tr:nth-child(even) { background: #faf9f5; }
.article-body .data-table code { font-family: var(--mono); font-size: .9em; background: var(--surface-2); padding: 1px 5px; border-radius: 4px; }
.table-wrap { overflow-x: auto; }

/* inline code */
.article-body p code, .article-body li code { font-family: var(--mono); font-size: .9em; background: var(--surface-2); padding: 1px 6px; border-radius: 5px; color: var(--accent-ink); word-break: break-word; }

/* code blocks */
.codeblock { position: relative; margin: 1.3em 0; }
.codeblock pre { background: var(--code-bg); color: var(--code-ink); border-radius: var(--radius-sm); padding: 18px; overflow-x: auto; font-size: 14.5px; line-height: 1.65; margin: 0; border: 1px solid #2c2b40; }
.codeblock code { font-family: var(--mono); }
.codeblock .tok-com { color: #8a89b8; font-style: italic; }
.codeblock .tok-str { color: #9ee493; }
.codeblock .tok-key { color: #c792ea; }
.codeblock .tok-fn  { color: #82aaff; }
.copy-btn { position: absolute; top: 10px; right: 10px; z-index: 2; font: inherit; font-size: 12px; font-weight: 700; background: rgba(255,255,255,.1); color: #fff; border: 1px solid rgba(255,255,255,.22); padding: 5px 11px; border-radius: 7px; cursor: pointer; }
.copy-btn:hover { background: rgba(255,255,255,.2); }
.copy-btn.copied { background: var(--ok); border-color: var(--ok); }

/* 더 깊이 (collapsible) */
details.deeper { margin: 1.5em 0; border: 1px solid var(--accent-bg); border-left: 4px solid var(--accent); border-radius: var(--radius-sm); background: linear-gradient(180deg, #f6f3ff, var(--surface)); overflow: hidden; }
details.deeper > summary { cursor: pointer; list-style: none; padding: 14px 18px; font-weight: 700; color: var(--accent-ink); display: flex; align-items: center; gap: 8px; user-select: none; }
details.deeper > summary::-webkit-details-marker { display: none; }
details.deeper > summary .chev { transition: transform .2s; }
details.deeper[open] > summary .chev { transform: rotate(90deg); }
details.deeper > summary .tag { font-size: 11px; font-weight: 700; margin-left: auto; color: var(--muted); background: var(--surface-2); padding: 2px 9px; border-radius: 999px; }
.deeper-body { padding: 2px 18px 18px; font-size: 16.5px; color: var(--ink-soft); }
.deeper-body p { margin: .8em 0; }
.deeper-body ul { margin: .6em 0; }
.deeper-body code { font-family: var(--mono); font-size: .92em; background: var(--surface-2); padding: 1px 6px; border-radius: 5px; }
.deeper-body .codeblock code { background: none; padding: 0; }

/* callout / warning */
.callout { margin: 1.4em 0; border-radius: var(--radius); padding: 16px 18px; border: 1px solid var(--border); background: var(--surface); box-shadow: var(--shadow); font-size: 16px; color: var(--ink-soft); }
.callout.warn { border-color: #f0d9a8; background: #fff8e8; }
.callout.warn strong { color: #8a6d00; }
.callout.note { border-color: var(--accent-bg); background: #faf9ff; }
.callout .c-title { font-weight: 800; display: flex; align-items: center; gap: 8px; margin-bottom: 6px; color: var(--ink); }

/* 지금 해보기 callout — 위젯으로 연결 */
.tryit { margin: 1.6em 0; border-radius: var(--radius); padding: 18px 20px; background: linear-gradient(180deg, #fff, #fbfaff); border: 1px solid var(--accent-bg); box-shadow: var(--shadow); }
.tryit-head { display: flex; align-items: center; gap: 9px; font-weight: 800; color: var(--accent-ink); font-size: 15px; margin-bottom: 8px; flex-wrap: wrap; }
.tryit-head .wrench { font-size: 18px; }
.tryit-head .act-id { font-size: 11.5px; font-weight: 700; color: var(--muted); background: var(--surface-2); padding: 2px 9px; border-radius: 999px; font-family: var(--mono); }
.tryit-head .lv { font-size: 12px; font-weight: 700; color: var(--muted); background: var(--surface-2); padding: 2px 9px; border-radius: 999px; }
.tryit p { margin: .4em 0 0; font-size: 15.5px; color: var(--ink-soft); }
.tryit p strong { color: var(--ink); }
.tryit .jump { margin-top: 12px; font: inherit; font-size: 14px; font-weight: 700; cursor: pointer; background: var(--accent); color: #fff; border: 0; padding: 10px 16px; border-radius: 9px; display: inline-flex; align-items: center; gap: 7px; }
.tryit .jump:hover { background: var(--accent-ink); }

/* ============================================================ WIDGET (iframe 임베드 셸) ============================================================ */
.widget { margin: 1.6em 0 2em; border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); box-shadow: var(--shadow-lg); overflow: hidden; scroll-margin-top: 80px; }
.w-banner { font-size: 12.5px; color: var(--accent-ink); background: var(--accent-bg); border-bottom: 1px solid #d9d0ff; padding: 9px 16px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.w-banner .em { font-weight: 800; }
.w-banner .actid { font-family: var(--mono); font-size: 11.5px; color: var(--muted); margin-left: auto; }
.widget-frame { display: block; width: 100%; border: 0; background: #0d1020; }
.w-fallback { font-size: 13px; color: var(--muted); background: var(--surface-2); border-top: 1px solid var(--border); padding: 10px 16px; }
.w-fallback a { font-weight: 700; }

/* ============================================================ BUTTONS ============================================================ */
.btn-primary, .btn-ghost, .btn-pending { font: inherit; font-weight: 700; cursor: pointer; border-radius: 9px; padding: 10px 16px; display: inline-flex; align-items: center; gap: 7px; transition: all .14s; line-height: 1.2; text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; border: 1.5px solid var(--accent); }
.btn-primary:hover { background: var(--accent-ink); border-color: var(--accent-ink); color: #fff; }
.btn-ghost { background: var(--surface); color: var(--accent-ink); border: 1.5px solid var(--accent-bg); }
.btn-ghost:hover { border-color: var(--accent); background: var(--accent-bg); }
.btn-pending { background: var(--surface-2); color: var(--muted); border: 1.5px dashed var(--border); cursor: help; }

/* ============================================================ SHARE BLOCK ============================================================ */
.share-block { margin: 1.8em 0; border: 1px solid var(--border); border-radius: var(--radius); background: linear-gradient(180deg,#fff,#fbfaff); padding: 20px 22px; box-shadow: var(--shadow); }
.share-block h3 { margin: 0 0 6px; font-size: 17px; display: flex; align-items: center; gap: 8px; }
.share-block p { margin: 0 0 14px; font-size: 15px; color: var(--muted); }
.share-tag { display: inline-block; font-family: var(--mono); font-weight: 700; font-size: 14px; color: var(--accent-ink); background: var(--accent-bg); padding: 3px 12px; border-radius: 999px; margin: 0 4px 8px 0; }
.share-actions { display: flex; gap: 9px; flex-wrap: wrap; margin-top: 4px; }
.share-note { font-size: 12.5px; color: var(--muted); margin-top: 14px; padding-top: 12px; border-top: 1px dashed var(--border); }
.share-note code { font-family: var(--mono); font-size: .92em; background: var(--surface-2); padding: 1px 6px; border-radius: 5px; }

/* toast */
.toast { position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%); z-index: 95; background: var(--ink); color: #fff; padding: 12px 20px; border-radius: 10px; font-size: 14px; box-shadow: var(--shadow-lg); opacity: 0; transition: opacity .25s, transform .25s; pointer-events: none; max-width: 90vw; text-align: center; }
.toast.show { opacity: 1; transform: translateX(-50%) translateY(-4px); }

/* article footer nav */
.article-nav { max-width: var(--maxtext); margin: 30px auto 60px; padding: 0 22px; display: flex; gap: 12px; justify-content: space-between; flex-wrap: wrap; }
.nav-card { flex: 1; min-width: 220px; border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; background: var(--surface); text-decoration: none; color: var(--ink); box-shadow: var(--shadow); transition: all .15s; }
.nav-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.nav-card.disabled { opacity: .5; pointer-events: none; }
.nav-card .dir { font-size: 12px; color: var(--muted); font-weight: 700; }
.nav-card .ttl { font-weight: 700; font-size: 15px; margin-top: 4px; }
.nav-card.next { text-align: right; }

footer.site { border-top: 1px solid var(--border); background: var(--surface); padding: 30px 22px; text-align: center; color: var(--muted); font-size: 13.5px; }
footer.site a { color: var(--accent-ink); }
footer.site code { font-family: var(--mono); font-size: .9em; }
footer.site .fseries { display: inline-flex; gap: 8px; flex-wrap: wrap; justify-content: center; margin-top: 8px; font-weight: 700; }

/* responsive */
@media (max-width: 640px) {
  body { font-size: 17px; }
  .article-body { font-size: 17px; }
  .card-grid { grid-template-columns: 1fr; }
  .masthead nav { display: none; }
  .article { padding-top: 26px; }
  .cover { padding-top: 40px; }
  .loop-strip .beat { font-size: 13px; padding: 6px 11px; }
}
@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; transition: none !important; animation: none !important; }
}