/* 강의 노트 디자인 — 외부 폰트/CDN 없음, 시스템 폰트 스택 */
:root {
  --bg: #f6f7fb;
  --surface: #ffffff;
  --text: #1c2030;
  --muted: #5d6478;
  --border: #e2e5ee;
  --accent: #3b5bdb;
  --accent-soft: #e7ecff;
  --accent-text: #ffffff;
  --code-bg: #14182a;
  --code-text: #e6e9f5;
  --tip-bg: #fff8e1;
  --tip-border: #f2b705;
  --tip-text: #5a4500;
  --shadow: 0 1px 2px rgba(20, 24, 42, .06), 0 4px 16px rgba(20, 24, 42, .06);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1220;
    --surface: #181c2e;
    --text: #e8eaf4;
    --muted: #a0a7bf;
    --border: #2a3050;
    --accent: #8ba2ff;
    --accent-soft: #232a52;
    --accent-text: #0f1220;
    --code-bg: #0a0c17;
    --code-text: #dfe3f5;
    --tip-bg: #2b2410;
    --tip-border: #d9a406;
    --tip-text: #f3deaa;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 4px 16px rgba(0, 0, 0, .3);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  -webkit-text-size-adjust: 100%;
}
a { color: var(--accent); }

/* 히어로 */
.hero {
  background: linear-gradient(135deg, #2b3a9e 0%, #5b3fc4 55%, #8a3fb8 100%);
  color: #fff;
  padding: 72px 24px 64px;
}
.hero-inner { max-width: 880px; margin: 0 auto; }
.hero-eyebrow { margin: 0 0 12px; font-size: .85rem; letter-spacing: .12em; text-transform: uppercase; opacity: .8; }
.hero-title { margin: 0 0 16px; font-size: 2.4rem; line-height: 1.25; letter-spacing: -.01em; word-break: keep-all; }
.hero-sub { margin: 0; font-size: 1.05rem; opacity: .88; max-width: 38em; }

/* 주차 내비게이션 */
.week-nav {
  position: sticky; top: 0; z-index: 10;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.week-nav ul {
  list-style: none; margin: 0 auto; padding: 10px 24px;
  max-width: 880px; display: flex; gap: 8px; overflow-x: auto;
}
.week-nav a {
  display: block; padding: 6px 16px; border-radius: 999px; white-space: nowrap;
  text-decoration: none; font-weight: 600; font-size: .92rem;
  color: var(--accent); background: var(--accent-soft);
}
.week-nav a:hover, .week-nav a:focus-visible { background: var(--accent); color: var(--accent-text); }

/* 본문 */
.content { max-width: 880px; margin: 0 auto; padding: 32px 24px 48px; }

/* 주차 카드 */
.week {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 32px;
  margin: 0 0 28px;
}
.week-header { margin: 0 0 24px; padding-bottom: 20px; border-bottom: 1px solid var(--border); }
.week-badge {
  display: inline-block; padding: 2px 12px; margin-bottom: 10px;
  border-radius: 999px; font-size: .8rem; font-weight: 700; letter-spacing: .04em;
  background: var(--accent); color: var(--accent-text);
}
.week-title { margin: 0 0 8px; font-size: 1.6rem; line-height: 1.3; word-break: keep-all; }
.week-summary { margin: 0; color: var(--muted); }

.topic { margin: 0 0 28px; }
.topic:last-child { margin-bottom: 0; }
.topic-title {
  margin: 0 0 10px; font-size: 1.15rem; line-height: 1.4;
  padding-left: 12px; border-left: 4px solid var(--accent);
}
.topic p { margin: 0 0 12px; }
.topic-list { margin: 0 0 14px; padding-left: 1.3em; }
.topic-list li { margin: 4px 0; }
.topic-list li::marker { color: var(--accent); }

/* 코드 블록 */
.code {
  margin: 0 0 16px; padding: 16px 18px; overflow-x: auto;
  background: var(--code-bg); color: var(--code-text);
  border-radius: 10px; border: 1px solid var(--border);
  font-family: var(--mono); font-size: .88rem; line-height: 1.6; tab-size: 2;
}
.code code { font-family: inherit; background: none; padding: 0; white-space: pre; }
p code, li code {
  font-family: var(--mono); font-size: .88em; padding: 1px 6px;
  background: var(--accent-soft); border-radius: 4px;
}

/* 팁 박스 */
.tip {
  margin: 0 0 16px; padding: 14px 16px 14px 18px;
  background: var(--tip-bg); color: var(--tip-text);
  border-left: 4px solid var(--tip-border); border-radius: 8px;
}
.tip::before { content: "💡 TIP"; display: block; margin-bottom: 4px; font-size: .78rem; font-weight: 700; letter-spacing: .06em; }
.tip > :last-child { margin-bottom: 0; }

.site-footer { text-align: center; padding: 24px; color: var(--muted); font-size: .85rem; border-top: 1px solid var(--border); }
.site-footer p { margin: 0; }

/* 반응형 */
@media (max-width: 768px) {
  body { font-size: 15px; }
  .hero { padding: 48px 18px 40px; }
  .hero-title { font-size: 1.7rem; }
  .week-nav ul { padding: 8px 14px; }
  .content { padding: 20px 14px 32px; }
  .week { padding: 20px 16px; border-radius: 12px; margin-bottom: 20px; }
  .week-title { font-size: 1.3rem; }
  .code { padding: 12px 14px; font-size: .82rem; }
}