:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --ink: #1a2233;
  --ink-soft: #5b6b85;
  --line: #e3e9f2;
  --accent: #2b6cb0;
  --accent-dark: #1e4e82;
  --accent-soft: #e8f1fb;
  --good: #2f855a;
  --radius: 14px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { font-size: 16px; }

body {
  font-family: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, system-ui, "Segoe UI", "Malgun Gothic", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: 860px; margin: 0 auto; padding: 0 20px; }

/* Header */
header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 10;
}
.nav {
  display: flex; align-items: center; justify-content: space-between;
  height: 60px;
}
.logo {
  font-weight: 800; font-size: 1.25rem; color: var(--ink);
  letter-spacing: -0.02em;
}
.logo span { color: var(--accent); }
.logo:hover { text-decoration: none; }
.nav-links { display: flex; gap: 18px; font-size: 0.92rem; }
.nav-links a { color: var(--ink-soft); font-weight: 500; }
.nav-links a:hover { color: var(--accent); text-decoration: none; }

/* Hero */
.hero { padding: 48px 0 8px; }
.hero h1 { font-size: 1.9rem; letter-spacing: -0.02em; line-height: 1.3; }
.hero p { color: var(--ink-soft); margin-top: 10px; max-width: 560px; }

/* Cards grid */
.grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px; margin: 32px 0 48px;
}
.tool-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; display: block; color: var(--ink);
  transition: box-shadow .15s, transform .15s;
}
.tool-card:hover {
  text-decoration: none; box-shadow: 0 8px 24px rgba(26,34,51,.08);
  transform: translateY(-2px);
}
.tool-card .icon { font-size: 1.6rem; }
.tool-card h3 { margin: 10px 0 6px; font-size: 1.06rem; }
.tool-card p { font-size: 0.88rem; color: var(--ink-soft); }

/* Calculator layout */
main { padding: 36px 0 60px; }
.page-title { font-size: 1.6rem; letter-spacing: -0.02em; }
.page-sub { color: var(--ink-soft); margin: 8px 0 26px; font-size: 0.95rem; }

.calc-card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 28px; margin-bottom: 24px;
}

.field { margin-bottom: 18px; }
.field label { display: block; font-weight: 600; font-size: 0.92rem; margin-bottom: 7px; }
.field .hint { font-weight: 400; color: var(--ink-soft); font-size: 0.82rem; margin-left: 6px; }

.input-row { position: relative; }
input[type="text"], input[type="number"], select {
  width: 100%; padding: 12px 52px 12px 14px;
  border: 1.5px solid var(--line); border-radius: 10px;
  font-size: 1.05rem; font-family: inherit; color: var(--ink);
  background: #fbfcfe; outline: none;
  transition: border-color .12s;
}
select { padding-right: 14px; }
input:focus, select:focus { border-color: var(--accent); background: #fff; }
.unit {
  position: absolute; right: 14px; top: 50%; transform: translateY(-50%);
  color: var(--ink-soft); font-size: 0.9rem; pointer-events: none;
}

.seg { display: flex; gap: 8px; flex-wrap: wrap; }
.seg button {
  flex: 1; min-width: 90px; padding: 10px 8px; border-radius: 10px;
  border: 1.5px solid var(--line); background: #fbfcfe; color: var(--ink-soft);
  font-family: inherit; font-size: 0.92rem; font-weight: 600; cursor: pointer;
}
.seg button.on { border-color: var(--accent); background: var(--accent-soft); color: var(--accent-dark); }

.btn {
  display: block; width: 100%; padding: 14px; margin-top: 8px;
  background: var(--accent); color: #fff; border: 0; border-radius: 10px;
  font-family: inherit; font-size: 1.05rem; font-weight: 700; cursor: pointer;
  transition: background .12s;
}
.btn:hover { background: var(--accent-dark); }

/* Results */
.result { display: none; }
.result.show { display: block; }
.result-hero {
  background: var(--accent-soft); border: 1px solid #cfe2f5;
  border-radius: var(--radius); padding: 24px; text-align: center; margin-bottom: 16px;
}
.result-hero .label { font-size: 0.9rem; color: var(--accent-dark); font-weight: 600; }
.result-hero .value { font-size: 2rem; font-weight: 800; letter-spacing: -0.02em; margin-top: 4px; }
.result-hero .value small { font-size: 1.1rem; font-weight: 600; }

table.breakdown { width: 100%; border-collapse: collapse; font-size: 0.94rem; }
table.breakdown th, table.breakdown td {
  padding: 10px 8px; border-bottom: 1px solid var(--line); text-align: right;
}
table.breakdown th { text-align: left; font-weight: 600; color: var(--ink-soft); }
table.breakdown tr.total td, table.breakdown tr.total th { font-weight: 800; border-bottom: 0; }
table.breakdown td.neg { color: #c53030; }

.note {
  font-size: 0.82rem; color: var(--ink-soft); background: #fbfcfe;
  border: 1px dashed var(--line); border-radius: 10px; padding: 12px 14px; margin-top: 16px;
}

/* Article / guide content */
.guide { margin-top: 40px; }
.guide h2 { font-size: 1.25rem; margin: 34px 0 12px; letter-spacing: -0.01em; }
.guide h3 { font-size: 1.05rem; margin: 22px 0 8px; }
.guide p { margin-bottom: 12px; color: #33405a; font-size: 0.96rem; }
.guide table { width: 100%; border-collapse: collapse; font-size: 0.9rem; margin: 14px 0; background: var(--card); }
.guide table th, .guide table td { border: 1px solid var(--line); padding: 9px 12px; text-align: left; }
.guide table th { background: #f0f4fa; font-weight: 700; }
.faq details {
  background: var(--card); border: 1px solid var(--line); border-radius: 10px;
  padding: 14px 18px; margin-bottom: 10px;
}
.faq summary { font-weight: 600; cursor: pointer; font-size: 0.95rem; }
.faq details p { margin: 10px 0 2px; font-size: 0.92rem; }

/* Footer */
footer {
  border-top: 1px solid var(--line); background: var(--card);
  padding: 28px 0; margin-top: 40px;
  font-size: 0.85rem; color: var(--ink-soft);
}
.foot-links { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 10px; }

/* Amortization table scroll */
.tbl-scroll { overflow-x: auto; margin-top: 16px; }
.tbl-scroll table { min-width: 520px; }

@media (max-width: 560px) {
  .hero h1 { font-size: 1.5rem; }
  .nav-links { gap: 12px; font-size: 0.85rem; }
  .calc-card { padding: 20px 16px; }
  .result-hero .value { font-size: 1.6rem; }
}