:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --text: #1b2330;
  --muted: #5d6878;
  --line: #e2e7ee;
  --brand: #1f5fd6;
  --brand-soft: #e8f0ff;
  --good: #0f8a5f;
  --good-soft: #e5f6ef;
  --bad: #c8372d;
  --bad-soft: #fdecea;
  --radius: 14px;
}
* { 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", "Noto Sans KR", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  word-break: keep-all;
}
a { color: var(--brand); }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 16px; }

/* 헤더 */
.site-header { background: var(--surface); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 10; }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 56px; flex-wrap: wrap; }
.logo { font-weight: 800; color: var(--text); text-decoration: none; font-size: 17px; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; }
.nav a { color: var(--muted); text-decoration: none; padding: 6px 10px; border-radius: 8px; font-size: 14px; }
.nav a[aria-current="page"], .nav a:hover { background: var(--brand-soft); color: var(--brand); }

h1 { font-size: 26px; line-height: 1.3; margin: 28px 0 6px; }
h2 { font-size: 20px; margin: 32px 0 12px; }
h3 { font-size: 17px; margin: 22px 0 8px; }
.lead { color: var(--muted); margin: 0 0 20px; }

.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; margin: 16px 0; }
.card h2 { margin-top: 0; }

/* 입력 폼 */
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px 20px; }
.field label { display: block; font-weight: 700; font-size: 15px; margin-bottom: 4px; }
.field .help { display: block; color: var(--muted); font-size: 13px; line-height: 1.45; margin-top: 4px; }
.input-box { position: relative; }
.input-box input {
  width: 100%; font-size: 17px; padding: 11px 44px 11px 12px; border: 1px solid #cfd6e0; border-radius: 10px;
  background: #fff; color: var(--text); text-align: right; font-variant-numeric: tabular-nums;
}
.input-box input:focus { outline: 2px solid var(--brand); outline-offset: 0; border-color: var(--brand); }
.input-box .unit { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--muted); font-size: 14px; pointer-events: none; }
.korean-amount { color: var(--brand); font-size: 13px; min-height: 1em; margin-top: 2px; text-align: right; }
fieldset { border: 0; padding: 0; margin: 0; }
legend { font-size: 18px; font-weight: 800; margin-bottom: 12px; padding: 0; }
.group + .group { margin-top: 26px; padding-top: 22px; border-top: 1px dashed var(--line); }

.actions { display: flex; gap: 10px; margin-top: 22px; flex-wrap: wrap; }
.btn { appearance: none; border: 0; border-radius: 10px; padding: 13px 22px; font-size: 16px; font-weight: 700; cursor: pointer; }
.btn-primary { background: var(--brand); color: #fff; flex: 1 1 200px; }
.btn-ghost { background: #eef1f5; color: var(--text); }

/* 결과 */
.result-hero { text-align: center; padding: 26px 16px; border-radius: var(--radius); }
.result-hero.refund { background: var(--good-soft); }
.result-hero.pay { background: var(--bad-soft); }
.result-hero .label { font-size: 16px; font-weight: 700; color: var(--muted); }
.result-hero .amount { font-size: 40px; font-weight: 900; letter-spacing: -0.5px; line-height: 1.2; margin: 6px 0; font-variant-numeric: tabular-nums; word-break: break-all; }
.result-hero.refund .amount { color: var(--good); }
.result-hero.pay .amount { color: var(--bad); }
.result-hero .sub { font-size: 14px; color: var(--muted); }

.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }
table { width: 100%; border-collapse: collapse; font-size: 15px; }
th, td { padding: 10px 8px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { font-size: 13px; color: var(--muted); font-weight: 700; background: #fafbfd; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }
tr.total td { font-weight: 800; border-top: 2px solid var(--text); }
.tag { display: inline-block; font-size: 11px; padding: 1px 6px; border-radius: 6px; background: #eef1f5; color: var(--muted); margin-left: 4px; vertical-align: 1px; white-space: nowrap; }
.zero { color: #a3acb9; }

.notice { background: #fff8e6; border: 1px solid #f2dfa7; border-radius: 10px; padding: 14px 16px; font-size: 15px; margin: 16px 0; }
.notice strong { color: #8a5a00; }
.small { font-size: 13px; color: var(--muted); }
details summary { cursor: pointer; font-weight: 700; padding: 6px 0; }
ul.plain { padding-left: 20px; }
ul.plain li { margin: 4px 0; }

/* 광고 자리 (애드센스 승인 후 실제 코드로 교체) */
.ad-slot {
  border: 2px dashed #c3cbd6; border-radius: 12px; background: repeating-linear-gradient(45deg, #fafbfc, #fafbfc 10px, #f2f4f7 10px, #f2f4f7 20px);
  color: #8a94a3; font-size: 13px; display: flex; align-items: center; justify-content: center; text-align: center;
  min-height: 100px; margin: 20px 0; padding: 12px;
}
.ad-slot.tall { min-height: 250px; }

/* 푸터 */
.site-footer { margin-top: 40px; padding: 24px 0 36px; border-top: 1px solid var(--line); background: var(--surface); font-size: 14px; color: var(--muted); }
.site-footer nav { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 8px; }
.site-footer a { color: var(--muted); }

@media (max-width: 640px) {
  h1 { font-size: 22px; margin-top: 20px; }
  .form-grid { grid-template-columns: 1fr; }
  .card { padding: 16px; }
  .result-hero .amount { font-size: 32px; }
  table { font-size: 14px; }
  th, td { padding: 9px 6px; }
  .logo { font-size: 16px; }
  .nav a { padding: 5px 8px; font-size: 13px; }
}