:root {
  --navy: #172542;
  --navy-2: #24365e;
  --cream: #fdfbf4;
  --bg: #f4f2ea;
  --card: #ffffff;
  --line: #e6e1cd;
  --text: #1d2433;
  --muted: #5d6475;
  --red: #d93b3b;
  --blue: #2f66cc;
  --accent: #f3b33d;
  --radius: 14px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --navy: #a9bde6;
    --navy-2: #c6d4f0;
    --cream: #1d2433;
    --bg: #12161f;
    --card: #1a2030;
    --line: #2c3448;
    --text: #e7eaf1;
    --muted: #9aa3b7;
    --red: #ff6b6b;
    --blue: #6f9cff;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Pretendard", "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif;
  line-height: 1.7;
  font-size: 16px;
}
a { color: var(--blue); }
.wrap { max-width: 860px; margin: 0 auto; padding: 0 16px; }

/* 헤더 */
.site-header { background: #172542; color: #fdfbf4; }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding-top: 14px; padding-bottom: 14px; flex-wrap: wrap; }
.logo { color: #fdfbf4; text-decoration: none; font-weight: 800; font-size: 20px; display: flex; align-items: center; gap: 8px; }
.logo-mark { display: inline-flex; gap: 3px; align-items: flex-end; height: 22px; }
.logo-mark i { display: block; width: 5px; border-radius: 1px; }
.logo-mark i:nth-child(1) { height: 10px; background: #6f9cff; }
.logo-mark i:nth-child(2) { height: 16px; background: #ff6b6b; }
.logo-mark i:nth-child(3) { height: 22px; background: #ff6b6b; }
.site-nav { display: flex; gap: 4px; flex-wrap: wrap; }
.site-nav a { color: #dfe5f2; text-decoration: none; font-size: 14px; padding: 6px 10px; border-radius: 8px; }
.site-nav a:hover, .site-nav a[aria-current="page"] { background: rgba(255,255,255,.12); color: #fff; }

/* 본문 */
main { padding: 28px 0 48px; }
h1 { font-size: 28px; line-height: 1.35; margin: 0 0 8px; color: var(--navy); }
h2 { font-size: 21px; margin: 40px 0 12px; color: var(--navy); }
h3 { font-size: 17px; margin: 24px 0 8px; }
.lead { color: var(--muted); margin: 0 0 24px; }
.badge { display: inline-block; font-size: 12px; font-weight: 700; background: var(--navy); color: var(--cream); padding: 2px 10px; border-radius: 999px; margin-bottom: 10px; }

/* 계산기 카드 */
.calc { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: 0 1px 0 rgba(0,0,0,.03); }
.fields { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px 16px; }
.field label { display: block; font-size: 14px; font-weight: 700; margin-bottom: 6px; }
.field .hint { font-size: 12px; color: var(--muted); margin-top: 4px; }
.input-unit { display: flex; align-items: stretch; border: 1px solid var(--line); border-radius: 10px; background: var(--cream); overflow: hidden; }
.input-unit:focus-within { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(47,102,204,.15); }
.input-unit input, .input-unit select { flex: 1; min-width: 0; border: 0; background: transparent; color: var(--text); font: inherit; font-size: 17px; padding: 10px 12px; text-align: right; outline: none; }
.input-unit select { text-align: left; }
.input-unit span { display: flex; align-items: center; padding: 0 12px; color: var(--muted); font-size: 14px; border-left: 1px solid var(--line); white-space: nowrap; }
.full { grid-column: 1 / -1; }
.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.seg button { border: 0; background: var(--cream); color: var(--text); padding: 8px 14px; font: inherit; font-size: 14px; cursor: pointer; }
.seg button + button { border-left: 1px solid var(--line); }
.seg button.on { background: var(--navy); color: var(--cream); font-weight: 700; }

/* 매수 내역 행 */
.rows { display: grid; gap: 10px; }
.row { display: grid; grid-template-columns: 28px minmax(0,1fr) minmax(0,1fr) 36px; gap: 10px; align-items: center; }
.row .num { font-size: 13px; color: var(--muted); text-align: center; }
.icon-btn { width: 36px; height: 36px; border: 1px solid var(--line); background: var(--cream); color: var(--muted); border-radius: 10px; cursor: pointer; font-size: 18px; line-height: 1; }
.icon-btn:hover { color: var(--red); }
.btn { border: 0; border-radius: 10px; padding: 10px 16px; font: inherit; font-weight: 700; cursor: pointer; }
.btn-ghost { background: transparent; border: 1px dashed var(--line); color: var(--navy); width: 100%; }
.btn-ghost:hover { border-color: var(--navy); }
.btn-sub { background: var(--cream); border: 1px solid var(--line); color: var(--text); font-weight: 600; font-size: 14px; }

/* 결과 */
.result { margin-top: 20px; border-radius: 12px; background: var(--navy); color: #fdfbf4; padding: 18px 20px; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .result { background: #24365e; } }
.result-main { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.result-main .label { font-size: 14px; opacity: .85; }
.result-main .value { font-size: 30px; font-weight: 800; letter-spacing: -0.5px; }
.result-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 8px 20px; margin-top: 14px; padding-top: 14px; border-top: 1px solid rgba(255,255,255,.18); font-size: 14px; }
.result-grid div { display: flex; justify-content: space-between; gap: 10px; }
.result-grid dt { opacity: .8; }
.result-grid dd { margin: 0; font-weight: 700; text-align: right; }
.up { color: #ff8a8a; }
.down { color: #8fb4ff; }
.note { font-size: 13px; color: var(--muted); margin-top: 10px; }

/* 표 */
.table-wrap { overflow-x: auto; margin: 12px 0; }
table { width: 100%; border-collapse: collapse; background: var(--card); font-size: 14px; }
th, td { border: 1px solid var(--line); padding: 8px 10px; text-align: right; white-space: nowrap; }
th { background: var(--cream); color: var(--navy); text-align: center; }
td:first-child { text-align: center; }

/* 본문 설명 */
.article p, .article li { color: var(--text); }
.article .box { background: var(--card); border: 1px solid var(--line); border-left: 4px solid var(--accent); border-radius: 10px; padding: 14px 16px; margin: 14px 0; }
.formula { font-family: ui-monospace, Consolas, monospace; background: var(--cream); border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; overflow-x: auto; font-size: 14px; }
details { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; margin: 8px 0; }
details summary { cursor: pointer; font-weight: 700; }
details p { margin: 8px 0 0; }

/* 홈 카드 */
.cards { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 14px; margin-top: 20px; }
.card { display: block; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; text-decoration: none; color: var(--text); transition: transform .12s, border-color .12s; }
.card:hover { transform: translateY(-2px); border-color: var(--navy); }
.card strong { display: block; font-size: 18px; color: var(--navy); margin-bottom: 4px; }
.card span { font-size: 14px; color: var(--muted); }
.related { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.related a { background: var(--card); border: 1px solid var(--line); border-radius: 999px; padding: 6px 12px; font-size: 14px; text-decoration: none; color: var(--navy); }

/* 푸터 */
.site-footer { border-top: 1px solid var(--line); padding: 24px 0 40px; font-size: 13px; color: var(--muted); }
.site-footer a { color: var(--muted); }
.site-footer .links { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 8px; }

@media (max-width: 640px) {
  h1 { font-size: 24px; }
  .fields, .cards, .result-grid { grid-template-columns: 1fr; }
  .calc { padding: 16px; }
  .result-main .value { font-size: 26px; }
  /* 매수 줄: 좁은 화면에서는 단위 칸을 숨겨 숫자 자리를 넓힌다 */
  .row { grid-template-columns: 18px minmax(0,1.5fr) minmax(0,1fr) 34px; gap: 6px; }
  .row .input-unit span { display: none; }
  .row .input-unit input { padding: 10px 8px; font-size: 16px; }
  .row .icon-btn { width: 34px; }
}