/* ======================================================
   INTERVIEW PREP — CSS (Mobile-First + Dark Mode + PWA)
   ====================================================== */

/* ── 1. CSS 변수 (라이트 테마) ── */
:root {
  --bg: #f0f4f8;
  --bg-gradient: linear-gradient(160deg, #e8f0fe 0%, #f0f4f8 60%, #f5f0ff 100%);
  --surface: #ffffff;
  --surface-2: #f8faff;
  --surface-3: #eef3fb;
  --surface-hover: #f1f5fd;
  --sidebar-bg: #0f172a;
  --sidebar-bg2: #111c31;
  --sidebar-text: #e5edf7;
  --sidebar-muted: rgba(229,237,247,0.65);
  --ink: #0f172a;
  --ink-2: #1e293b;
  --muted: #5b6a7d;
  --line: #dde4ee;
  --line-strong: #c5d0e0;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-2: #0f766e;
  --danger: #dc2626;
  --good: #16a34a;
  --good-bg: rgba(22,163,74,0.08);
  --orange: #f1593a;
  --orange-bg: rgba(241,89,58,0.10);
  --yellow: #d97706;
  --yellow-bg: rgba(217,119,6,0.08);
  --shadow-xs: 0 1px 3px rgba(15,23,42,0.06);
  --shadow: 0 4px 16px rgba(15,23,42,0.08);
  --shadow-md: 0 8px 24px rgba(15,23,42,0.10);
  --shadow-lg: 0 16px 40px rgba(15,23,42,0.12);
  --radius: 14px;
  --radius-sm: 10px;
  --radius-xs: 7px;
  --header-h: 56px;
  --sidebar-w: 300px;
  --transition: 0.18s cubic-bezier(.4,0,.2,1);
}

/* ── 다크 테마 ── */
[data-theme="dark"] {
  --bg: #0b1120;
  --bg-gradient: linear-gradient(160deg, #0f172a 0%, #0b1120 60%, #120f1f 100%);
  --surface: #131f35;
  --surface-2: #1a2744;
  --surface-3: #1e2f4e;
  --surface-hover: #1f3050;
  --sidebar-bg: #080e1a;
  --sidebar-bg2: #0a1120;
  --sidebar-text: #c8d8f0;
  --sidebar-muted: rgba(200,216,240,0.55);
  --ink: #e2ecf8;
  --ink-2: #c8d8f0;
  --muted: #8499b8;
  --line: #1e2f4e;
  --line-strong: #253a5e;
  --accent: #60a5fa;
  --accent-hover: #93c5fd;
  --accent-2: #2dd4bf;
  --good: #4ade80;
  --good-bg: rgba(74,222,128,0.10);
  --orange: #fb923c;
  --orange-bg: rgba(251,146,60,0.12);
  --yellow: #fbbf24;
  --yellow-bg: rgba(251,191,36,0.10);
  --shadow-xs: 0 1px 3px rgba(0,0,0,0.25);
  --shadow: 0 4px 16px rgba(0,0,0,0.30);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.35);
  --shadow-lg: 0 16px 40px rgba(0,0,0,0.40);
}

/* ── 2. 리셋 & 기본 ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  min-height: 100vh;
  min-height: 100dvh;
  background: var(--bg-gradient);
  color: var(--ink);
  font-family: "Pretendard", "Apple SD Gothic Neo", "Malgun Gothic", "Segoe UI", sans-serif;
  line-height: 1.65;
  transition: background var(--transition), color var(--transition);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
button, input { font: inherit; cursor: pointer; }
button { border: none; background: none; }
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ── 3. Skip Link ── */
.skip-link {
  position: absolute; left: 12px; top: 12px; z-index: 200;
  transform: translateY(-200%); transition: transform var(--transition);
  padding: 10px 16px; border-radius: 999px;
  background: var(--surface); color: var(--ink);
  border: 1px solid var(--line); box-shadow: var(--shadow);
}
.skip-link:focus { transform: translateY(0); }

/* ── 4. 모바일 헤더 ── */
.mobile-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: var(--sidebar-bg);
  border-bottom: 1px solid rgba(255,255,255,0.06);
  box-shadow: var(--shadow-md);
  safe-area-inset-top: env(safe-area-inset-top);
  padding-top: env(safe-area-inset-top, 0);
}
.mobile-header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: var(--header-h); padding: 0 16px;
}
.mobile-brand { display: flex; align-items: center; gap: 10px; }
.mobile-logo { font-size: 22px; }
.mobile-title { color: #fff; font-size: 17px; font-weight: 700; letter-spacing: -0.3px; }
.mobile-header-actions { display: flex; align-items: center; gap: 4px; }

.icon-btn {
  width: 40px; height: 40px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  color: rgba(255,255,255,0.85); font-size: 18px;
  transition: background var(--transition), transform var(--transition);
  background: transparent; border: none;
}
.icon-btn:hover, .icon-btn:active { background: rgba(255,255,255,0.10); transform: scale(1.05); }
.icon-btn.active { background: rgba(96,165,250,0.18); }

/* 진행 바 */
.progress-bar-wrapper {
  height: 3px; background: rgba(255,255,255,0.08);
}
.progress-bar {
  height: 100%; background: linear-gradient(90deg, #2563eb, #7c3aed);
  transition: width 0.5s ease; width: 0%;
  border-radius: 0 2px 2px 0;
}

/* ── 5. 레이아웃 Shell ── */
.shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  min-height: 100vh;
  padding-top: calc(var(--header-h) + env(safe-area-inset-top, 0));
  max-width: 1440px; margin: 0 auto;
}

/* ── 6. 사이드바 ── */
.sidebar {
  position: sticky; top: calc(var(--header-h) + env(safe-area-inset-top, 0));
  height: calc(100vh - var(--header-h) - env(safe-area-inset-top, 0));
  overflow-y: auto; overflow-x: hidden;
  background: var(--sidebar-bg);
  border-right: 1px solid rgba(255,255,255,0.06);
  scrollbar-width: thin;
  scrollbar-color: rgba(255,255,255,0.15) transparent;
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.15); border-radius: 4px; }

.sidebar-inner { padding: 20px 16px 24px; }
.sidebar-overlay { display: none; }

.brand { margin-bottom: 16px; }
.brand-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 8px; margin-bottom: 8px; }
.eyebrow {
  font-size: 10px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--sidebar-muted); margin-bottom: 6px; font-weight: 600;
}
.brand h1 {
  color: var(--sidebar-text); font-size: 18px; line-height: 1.3;
  font-family: Georgia, serif; font-weight: 700;
}
.brand p { color: var(--sidebar-muted); font-size: 13px; line-height: 1.5; }
.sidebar-close { display: none; color: var(--sidebar-muted); font-size: 18px; padding: 4px; }

/* 통계 요약 */
.summary {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px;
  padding: 12px; margin-bottom: 12px;
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-sm);
  background: rgba(255,255,255,0.04);
}
.metric { display: flex; flex-direction: column; gap: 2px; }
.metric span { color: var(--sidebar-muted); font-size: 11px; }
.metric strong { color: #ff5d4a; font-size: 20px; font-weight: 700; font-variant-numeric: tabular-nums; }

/* 원형 진행률 */
.progress-ring-wrapper {
  position: relative; width: 80px; height: 80px;
  margin: 8px auto 16px;
}
.progress-ring { transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: rgba(255,255,255,0.08); stroke-width: 8; }
.ring-fg {
  fill: none; stroke: #2563eb; stroke-width: 8;
  stroke-linecap: round;
  transition: stroke-dashoffset 0.6s ease;
}
.ring-label {
  position: absolute; inset: 0;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
}
.ring-label span { color: #fff; font-size: 14px; font-weight: 700; }
.ring-label small { color: var(--sidebar-muted); font-size: 10px; }

/* 툴바 (사이드바 내) */
.toolbar {
  padding: 12px; margin-bottom: 12px;
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-sm);
  background: rgba(255,255,255,0.03);
  display: grid; gap: 10px;
}
.search-input-wrap {
  position: relative;
}
.search-icon {
  position: absolute; left: 12px; top: 50%; transform: translateY(-50%);
  font-size: 14px; pointer-events: none;
}
.search-row input {
  width: 100%; height: 42px;
  padding: 0 12px 0 36px;
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius-xs);
  background: rgba(255,255,255,0.06);
  color: var(--sidebar-text); font-size: 14px;
  outline: none;
  transition: border-color var(--transition), background var(--transition);
}
.search-row input::placeholder { color: var(--sidebar-muted); }
.search-row input:focus {
  border-color: rgba(96,165,250,0.5);
  background: rgba(255,255,255,0.10);
}
.toolbar-btns { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.toolbar-btns .primary { grid-column: 1 / -1; }

.action {
  min-height: 36px; padding: 8px 12px;
  border-radius: var(--radius-xs); font-size: 13px; font-weight: 500;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(255,255,255,0.07); color: var(--sidebar-text);
  transition: background var(--transition), transform var(--transition), border-color var(--transition);
  white-space: nowrap;
}
.action:hover { background: rgba(255,255,255,0.12); transform: translateY(-1px); }
.action.primary {
  background: rgba(37,99,235,0.8); border-color: rgba(37,99,235,0.5); color: #fff;
}
.action.primary:hover { background: rgba(37,99,235,1); }

.statusbar {
  display: flex; flex-direction: column; gap: 2px;
  color: var(--sidebar-muted); font-size: 11px;
}

/* Nav */
.nav {
  display: grid; gap: 4px; margin-bottom: 16px;
}
.nav button {
  display: flex; align-items: center; justify-content: space-between;
  gap: 8px; width: 100%; min-height: 40px; padding: 9px 12px;
  border: 1px solid transparent; border-radius: var(--radius-xs);
  background: transparent; color: var(--sidebar-text); font-size: 13px;
  text-align: left; transition: background var(--transition), border-color var(--transition);
}
.nav button:hover { background: rgba(255,255,255,0.06); border-color: rgba(255,255,255,0.08); }
.nav button[aria-current="true"] {
  background: rgba(37,99,235,0.18); border-color: rgba(96,165,250,0.3);
  color: #93c5fd;
}
.nav .nav-item-label { display: flex; flex-direction: column; gap: 1px; }
.nav .nav-item-sub { font-size: 11px; opacity: 0.65; }
.nav small {
  color: rgba(229,237,247,0.65); font-size: 11px; font-variant-numeric: tabular-nums;
  flex: 0 0 auto;
}

/* 사이드바 푸터 */
.sidebar-footer {
  padding-top: 16px; margin-top: 8px;
  border-top: 1px solid rgba(255,255,255,0.07);
}
.note-label { color: var(--sidebar-muted); font-size: 10px; text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 6px; }
.note-content { color: var(--sidebar-muted); font-size: 12px; line-height: 1.7; }

/* ── 7. 콘텐츠 영역 ── */
.content {
  min-width: 0; padding: 16px 20px 40px;
  background: transparent;
}

/* 모바일 칩 행 */
.chip-row-mobile {
  display: none;
  gap: 6px; overflow-x: auto; padding: 0 2px 8px;
  scrollbar-width: none; margin-bottom: 8px;
}
.chip-row-mobile::-webkit-scrollbar { display: none; }
.chip {
  flex: 0 0 auto; min-height: 32px; padding: 6px 14px;
  border-radius: 999px; border: 1px solid var(--line);
  background: var(--surface); color: var(--muted); font-size: 13px;
  font-weight: 500; transition: background var(--transition), color var(--transition), border-color var(--transition);
  white-space: nowrap;
}
.chip:hover { background: var(--surface-hover); border-color: var(--line-strong); }
.chip.active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* ── 8. 퀴즈 패널 ── */
.quiz-panel {
  margin-bottom: 20px; padding: 20px;
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow-md);
}
.quiz-header { margin-bottom: 16px; }
.quiz-header h2 { font-size: 20px; margin-bottom: 6px; }
.quiz-header p { color: var(--muted); font-size: 14px; }
.quiz-stats {
  display: flex; align-items: center; gap: 16px;
  margin-top: 10px; font-size: 14px; font-variant-numeric: tabular-nums;
}
.quiz-score { margin-left: auto; }
.quiz-card {
  padding: 20px; background: var(--surface-2);
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  margin-bottom: 16px; min-height: 140px;
}
.quiz-question-text { font-size: 18px; font-weight: 600; line-height: 1.5; margin-bottom: 16px; }
.quiz-actions { display: flex; gap: 10px; }
.quiz-answer { margin-top: 16px; }
.quiz-answer-text {
  padding: 14px; background: var(--surface-3);
  border-radius: var(--radius-xs); font-size: 15px; line-height: 1.7;
  color: var(--ink-2); margin-bottom: 14px;
}
.quiz-result-btns { display: flex; gap: 10px; }
.quiz-btn {
  flex: 1; min-height: 44px; border-radius: var(--radius-sm);
  font-size: 15px; font-weight: 600; transition: transform var(--transition), opacity var(--transition);
  border: none;
}
.quiz-btn:hover { transform: translateY(-2px); }
.quiz-btn-correct { background: var(--good); color: #fff; }
.quiz-btn-wrong { background: var(--danger); color: #fff; }
.quiz-nav {
  display: flex; gap: 8px; flex-wrap: wrap;
}
.quiz-nav .action { flex: 1; min-width: 80px; text-align: center; justify-content: center; }

/* ── 9. 섹션 & 카드 ── */
.sections { display: grid; gap: 20px; }

.section {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: box-shadow var(--transition);
}
.section:hover { box-shadow: var(--shadow-md); }

.section-head {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; flex-wrap: wrap;
  padding: 16px 20px;
  background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
  color: #fff;
  border-bottom: 3px solid rgba(255,255,255,0.12);
}
.section-head h3 { font-size: 17px; font-weight: 700; }
.section-head p { font-size: 13px; color: rgba(255,255,255,0.8); }
.section-head .count-badge {
  flex: 0 0 auto; padding: 4px 10px; border-radius: 999px;
  background: rgba(255,255,255,0.18); font-size: 12px; font-weight: 600;
}

.qa-list { display: grid; gap: 0; }
.qa-list > *:not(:last-child) { border-bottom: 1px solid var(--line); }

/* QA 카드 */
.qa {
  background: var(--surface);
  transition: background var(--transition);
}
.qa:hover { background: var(--surface-hover); }
.qa[hidden] { display: none !important; }
.qa.memorized { border-left: 3px solid var(--good); }

.qa summary {
  list-style: none; display: flex; align-items: flex-start;
  gap: 12px; padding: 14px 16px; cursor: pointer; outline: none;
}
.qa summary::-webkit-details-marker { display: none; }
.qa summary:focus-visible { box-shadow: inset 0 0 0 2px rgba(37,99,235,0.5); }

.qa-title-area { flex: 1; min-width: 0; display: grid; gap: 6px; }
.badge-row { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }

.qnum {
  display: inline-flex; align-items: center;
  min-height: 22px; padding: 0 9px;
  border-radius: 999px;
  background: var(--orange); color: #fff;
  font-size: 11px; font-weight: 700;
}
.badge {
  display: inline-flex; align-items: center;
  min-height: 22px; padding: 0 8px;
  border-radius: 999px; border: 1px solid var(--line);
  background: var(--surface-2); color: var(--muted);
  font-size: 11px; white-space: nowrap;
}
.badge.primary {
  background: var(--orange-bg); color: var(--orange); border-color: rgba(241,89,58,0.2);
}
.qa.memorized .badge.primary {
  background: var(--good-bg); color: var(--good); border-color: rgba(22,163,74,0.2);
}

.question { font-size: 15px; line-height: 1.55; color: var(--ink); font-weight: 500; }
.summary-meta { color: var(--muted); font-size: 12px; }

.caret {
  flex: 0 0 auto; color: var(--muted); font-size: 16px;
  transition: transform var(--transition); padding-top: 2px; line-height: 1;
}
.qa[open] .caret { transform: rotate(180deg); }

/* QA 바디 */
.qa-body {
  display: grid; gap: 12px;
  padding: 0 16px 16px;
  border-top: 1px solid var(--line);
  background: var(--surface-2);
  transition: background var(--transition);
}
.qa-body.answers-collapsed .answer-content,
.qa-body.answers-collapsed .followup-list { display: none; }

.answer-block { display: grid; gap: 6px; padding-top: 12px; }
.label {
  font-size: 10px; letter-spacing: 0.09em; text-transform: uppercase;
  color: var(--accent-2); font-weight: 700;
}

.answer, .memo, .intent { margin: 0; min-width: 0; font-size: 14px; line-height: 1.7; }
.answer { color: var(--ink-2); }

.answer-stack { display: grid; gap: 8px; }
.answer-line {
  display: grid; grid-template-columns: 40px minmax(0, 1fr);
  gap: 10px; align-items: start;
  padding: 10px 12px 10px 10px;
  border: 1px solid rgba(37,99,235,0.08); border-radius: var(--radius-xs);
  background: var(--surface);
  transition: background var(--transition);
}
.answer-index {
  width: 40px; min-width: 40px; height: 26px; border-radius: 999px;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--orange-bg); color: var(--orange); font-weight: 700; font-size: 11px;
}

.followup-block { padding-top: 12px; border-top: 1px dashed var(--line); }
.followup-list { display: grid; gap: 8px; }
.followup-card {
  padding: 12px; border: 1px solid rgba(37,99,235,0.10);
  border-radius: var(--radius-xs);
  background: var(--surface-3);
  transition: background var(--transition);
}
.followup-head { display: grid; grid-template-columns: auto 1fr; gap: 8px; align-items: start; margin-bottom: 8px; }
.followup-num {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 36px; min-height: 22px; padding: 0 8px; border-radius: 999px;
  background: rgba(37,99,235,0.10); color: var(--accent); font-size: 11px; font-weight: 700;
}
.followup-question { margin: 0; font-size: 13px; line-height: 1.5; color: var(--ink); font-weight: 500; }
.followup-answer { padding-left: 2px; }

.memo {
  padding: 10px 12px; border-radius: var(--radius-xs);
  border: 1px solid var(--yellow-bg); background: var(--yellow-bg); color: var(--yellow);
}
[data-theme="dark"] .memo { color: #fcd34d; }

.intent { color: var(--muted); font-size: 13px; }

/* QA 액션 버튼 */
.qa-actions {
  display: flex; gap: 8px; flex-wrap: wrap; padding-top: 4px;
}
.qa-actions button {
  min-height: 34px; padding: 7px 11px; border-radius: var(--radius-xs);
  border: 1px solid var(--line); background: var(--surface); color: var(--ink);
  font-size: 12px; font-weight: 500;
  transition: background var(--transition), transform var(--transition), border-color var(--transition);
}
.qa-actions button:hover { transform: translateY(-1px); border-color: var(--line-strong); background: var(--surface-hover); }
.qa-actions .answer-toggle {
  background: rgba(37,99,235,0.06); border-color: rgba(37,99,235,0.15); color: var(--accent);
}
.qa-actions .memo-btn {
  background: var(--good-bg); border-color: rgba(22,163,74,0.2); color: var(--good);
}
.qa-actions .copy-btn {
  background: rgba(15,118,110,0.06); border-color: rgba(15,118,110,0.15); color: var(--accent-2);
}

/* ── 10. 푸터 ── */
.footer {
  margin: 24px 0 8px; color: var(--muted); font-size: 13px; line-height: 1.7;
}

/* ── 12. 반응형 ── */

/* 태블릿/데스크탑 (1024px+) */
@media (min-width: 1024px) {
  .mobile-header-actions .menu-btn { display: none; }
  .sidebar-close { display: none !important; }
  .chip-row-mobile { display: none !important; }
}

/* 모바일/태블릿 (1023px 이하) */
@media (max-width: 1023px) {
  .shell { grid-template-columns: 1fr; }

  /* 사이드바 = 드로어 */
  .sidebar {
    position: fixed; top: 0; left: 0; bottom: 0; z-index: 120;
    width: min(var(--sidebar-w), 85vw); height: 100%;
    transform: translateX(-100%); transition: transform 0.28s cubic-bezier(.4,0,.2,1);
    padding-top: env(safe-area-inset-top, 0);
    overflow-y: auto;
  }
  .sidebar.open { transform: translateX(0); }

  .sidebar-overlay {
    display: block; position: fixed; inset: 0; z-index: 110;
    background: rgba(0,0,0,0.55); opacity: 0; pointer-events: none;
    transition: opacity 0.28s ease;
  }
  .sidebar.open .sidebar-overlay { opacity: 1; pointer-events: auto; }

  .sidebar-close { display: flex !important; }

  .chip-row-mobile { display: flex; }
  .content { padding: 12px 14px 60px; }

  .nav { display: none; }
  .toolbar .statusbar { display: none; }
}

/* 소형 모바일 (480px 이하) */
@media (max-width: 480px) {
  .question { font-size: 14px; }
  .qa summary { padding: 12px 14px; }
  .qa-body { padding: 0 12px 14px; }
  .quiz-panel { padding: 14px; }
  .quiz-question-text { font-size: 16px; }
  .section-head { padding: 12px 14px; }
  .answer-line { grid-template-columns: 32px 1fr; }
  .answer-index { width: 32px; min-width: 32px; }
  .qa-actions { gap: 6px; }
  .qa-actions button { padding: 6px 8px; font-size: 11px; }
}

/* 접근성: 모션 감소 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ── 13. 성능 최적화 ── */
.section { content-visibility: auto; contain-intrinsic-size: 600px; }
.qa { content-visibility: auto; contain-intrinsic-size: 200px; }

/* ── 14. 다크모드 세부 조정 ── */
[data-theme="dark"] .section-head {
  background: linear-gradient(135deg, #1e40af 0%, #1e3a8a 100%);
}
[data-theme="dark"] .answer-line {
  border-color: rgba(96,165,250,0.08);
}
[data-theme="dark"] .followup-card {
  border-color: rgba(96,165,250,0.10);
}
[data-theme="dark"] .chip { background: var(--surface-2); border-color: var(--line); color: var(--muted); }
[data-theme="dark"] .chip.active { background: var(--accent); color: #0f172a; }
/* ── 15. 프린트 ── */
@media print {
  .mobile-header, .sidebar { display: none !important; }
  .shell { grid-template-columns: 1fr; }
  .content { padding: 0; }
  .qa-actions { display: none; }
}