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

:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --bg: #f8f9fa;
  --card-bg: #ffffff;
  --text: #202124;
  --text-muted: #5f6368;
  --border: #e0e0e0;
  --success: #34a853;
  --radius: 12px;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
}

body {
  font-family: 'Pretendard', 'Apple SD Gothic Neo', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

/* Header */
header {
  background: var(--primary);
  color: white;
  padding: 0 20px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

header .header-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  height: 56px;
  gap: 16px;
}

header .logo {
  font-size: 18px;
  font-weight: 700;
  text-decoration: none;
  color: white;
  white-space: nowrap;
}

header nav {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  scrollbar-width: none;
}

header nav::-webkit-scrollbar { display: none; }

header nav a {
  color: rgba(255,255,255,0.85);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: 20px;
  font-size: 14px;
  white-space: nowrap;
  transition: background 0.2s;
}

header nav a:hover,
header nav a.active {
  background: rgba(255,255,255,0.2);
  color: white;
}

/* Layout */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 16px;
}

/* Ad zones */
.ad-zone {
  background: #f1f3f4;
  border: 1px dashed #ccc;
  border-radius: var(--radius);
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
  padding: 16px;
  margin: 20px 0;
}

.ad-zone.horizontal {
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.ad-zone.rectangle {
  min-height: 250px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Main grid (index) */
.hero {
  text-align: center;
  padding: 40px 16px 24px;
}

.hero h1 {
  font-size: 28px;
  font-weight: 800;
  margin-bottom: 8px;
}

.hero p {
  color: var(--text-muted);
  font-size: 16px;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.calc-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.2s, box-shadow 0.2s;
  border: 1px solid var(--border);
  display: block;
}

.calc-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

.calc-card .icon {
  font-size: 36px;
  margin-bottom: 12px;
}

.calc-card h2 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 6px;
}

.calc-card p {
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.5;
}

.calc-card .tag {
  display: inline-block;
  background: #e8f0fe;
  color: var(--primary);
  font-size: 11px;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 10px;
  margin-top: 10px;
}

/* Calculator page layout */
.calc-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 24px;
  align-items: start;
}

@media (max-width: 768px) {
  .calc-layout {
    grid-template-columns: 1fr;
  }
}

/* Calculator card */
.calc-box {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px;
  border: 1px solid var(--border);
}

.calc-box h1 {
  font-size: 22px;
  font-weight: 800;
  margin-bottom: 6px;
}

.calc-box .desc {
  color: var(--text-muted);
  font-size: 14px;
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}

/* Form elements */
.form-group {
  margin-bottom: 18px;
}

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text);
}

.form-group .hint {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 12px;
  margin-left: 6px;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  color: var(--text);
  background: white;
  transition: border-color 0.2s;
  outline: none;
}

.form-group input:focus,
.form-group select:focus {
  border-color: var(--primary);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.radio-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 400;
  cursor: pointer;
  padding: 8px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  transition: all 0.2s;
  margin-bottom: 0;
}

.radio-group input[type="radio"] {
  display: none;
}

.radio-group input[type="radio"]:checked + span {
  color: var(--primary);
}

.radio-group label:has(input:checked) {
  border-color: var(--primary);
  background: #e8f0fe;
  color: var(--primary);
  font-weight: 600;
}

.btn-calc {
  width: 100%;
  padding: 14px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.2s;
  margin-top: 8px;
}

.btn-calc:hover {
  background: var(--primary-dark);
}

/* Result */
.result-box {
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  display: none;
}

.result-box.show {
  display: block;
}

.result-highlight {
  background: linear-gradient(135deg, #1a73e8, #0d47a1);
  color: white;
  border-radius: 10px;
  padding: 20px 24px;
  margin-bottom: 16px;
  text-align: center;
}

.result-highlight .label {
  font-size: 13px;
  opacity: 0.85;
  margin-bottom: 4px;
}

.result-highlight .value {
  font-size: 28px;
  font-weight: 800;
}

.result-highlight .sub {
  font-size: 13px;
  opacity: 0.75;
  margin-top: 4px;
}

.result-table {
  width: 100%;
  border-collapse: collapse;
}

.result-table tr {
  border-bottom: 1px solid var(--border);
}

.result-table tr:last-child {
  border-bottom: none;
}

.result-table td {
  padding: 12px 4px;
  font-size: 14px;
}

.result-table td:first-child {
  color: var(--text-muted);
  width: 45%;
}

.result-table td:last-child {
  font-weight: 600;
  text-align: right;
}

.result-table tr.total td {
  font-weight: 700;
  font-size: 15px;
  color: var(--primary);
}

/* Sidebar */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.info-box {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  border: 1px solid var(--border);
}

.info-box h3 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.info-box ul {
  padding-left: 18px;
}

.info-box ul li {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 6px;
  line-height: 1.5;
}

.info-box ul li strong {
  color: var(--text);
}

/* Related calc */
.related-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.related-link {
  display: block;
  padding: 10px 12px;
  background: var(--bg);
  border-radius: 8px;
  text-decoration: none;
  color: var(--text);
  font-size: 13px;
  font-weight: 600;
  text-align: center;
  border: 1px solid var(--border);
  transition: all 0.2s;
}

.related-link:hover {
  background: #e8f0fe;
  border-color: var(--primary);
  color: var(--primary);
}

/* Blog */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 24px 0;
}

.blog-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  text-decoration: none;
  color: var(--text);
  transition: transform 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
}

.blog-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

.blog-card-body {
  padding: 24px;
  flex: 1;
}

.blog-card .category {
  display: inline-block;
  background: #e8f0fe;
  color: var(--primary);
  font-size: 11px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 10px;
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.blog-card h2 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.4;
}

.blog-card p {
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.6;
}

.blog-card .meta {
  font-size: 12px;
  color: #999;
  margin-top: 12px;
}

.blog-card .read-more {
  padding: 14px 24px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  font-weight: 600;
  color: var(--primary);
}

/* Blog article */
.blog-article {
  max-width: 760px;
  margin: 0 auto;
}

.blog-article .article-header {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 32px;
  margin-bottom: 24px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.blog-article .article-header .category {
  display: inline-block;
  background: #e8f0fe;
  color: var(--primary);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 10px;
  margin-bottom: 14px;
}

.blog-article h1 {
  font-size: 26px;
  font-weight: 800;
  line-height: 1.35;
  margin-bottom: 12px;
}

.blog-article .article-meta {
  font-size: 13px;
  color: #999;
  margin-bottom: 16px;
}

.blog-article .article-intro {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.7;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.article-body {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 32px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  line-height: 1.8;
}

.article-body h2 {
  font-size: 20px;
  font-weight: 700;
  margin: 32px 0 14px;
  color: var(--text);
  padding-bottom: 8px;
  border-bottom: 2px solid var(--primary);
  display: inline-block;
}

.article-body h2:first-child {
  margin-top: 0;
}

.article-body h3 {
  font-size: 17px;
  font-weight: 700;
  margin: 24px 0 10px;
  color: var(--text);
}

.article-body p {
  margin-bottom: 16px;
  color: #333;
  font-size: 15px;
}

.article-body ul, .article-body ol {
  padding-left: 24px;
  margin-bottom: 16px;
}

.article-body li {
  margin-bottom: 8px;
  font-size: 15px;
  color: #333;
}

.article-body .highlight-box {
  background: #e8f0fe;
  border-left: 4px solid var(--primary);
  border-radius: 0 8px 8px 0;
  padding: 16px 20px;
  margin: 20px 0;
}

.article-body .highlight-box p {
  margin: 0;
  font-weight: 600;
  color: var(--primary-dark);
}

.article-body .warning-box {
  background: #fff8e1;
  border-left: 4px solid #f9a825;
  border-radius: 0 8px 8px 0;
  padding: 16px 20px;
  margin: 20px 0;
}

.article-body .warning-box p {
  margin: 0;
  color: #795548;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 14px;
}

.article-body table th {
  background: #f1f3f4;
  padding: 10px 12px;
  text-align: left;
  font-weight: 700;
  border: 1px solid var(--border);
}

.article-body table td {
  padding: 10px 12px;
  border: 1px solid var(--border);
}

.article-body table tr:nth-child(even) td {
  background: #fafafa;
}

.calc-cta {
  background: linear-gradient(135deg, #1a73e8, #0d47a1);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  margin: 28px 0;
  color: white;
}

.calc-cta p {
  color: rgba(255,255,255,0.85);
  margin-bottom: 12px;
  font-size: 15px;
}

.calc-cta a {
  display: inline-block;
  background: white;
  color: var(--primary);
  font-weight: 700;
  font-size: 15px;
  padding: 12px 28px;
  border-radius: 8px;
  text-decoration: none;
  transition: opacity 0.2s;
}

.calc-cta a:hover { opacity: 0.9; }

/* Footer */
footer {
  background: #2d2d2d;
  color: #aaa;
  text-align: center;
  padding: 32px 16px;
  margin-top: 40px;
  font-size: 13px;
  line-height: 2;
}

footer a {
  color: #ccc;
  text-decoration: none;
}

/* Amortization table */
.amort-table-wrap {
  overflow-x: auto;
  margin-top: 16px;
}

.amort-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.amort-table th {
  background: #f1f3f4;
  padding: 8px 10px;
  text-align: right;
  font-weight: 600;
  border-bottom: 2px solid var(--border);
}

.amort-table th:first-child { text-align: center; }

.amort-table td {
  padding: 7px 10px;
  text-align: right;
  border-bottom: 1px solid #f0f0f0;
}

.amort-table td:first-child { text-align: center; color: var(--text-muted); }

.amort-table tr:hover td { background: #fafafa; }

.tab-btns {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.tab-btn {
  padding: 8px 16px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  background: white;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  color: var(--text-muted);
  transition: all 0.2s;
}

.tab-btn.active {
  border-color: var(--primary);
  background: #e8f0fe;
  color: var(--primary);
}

@media (max-width: 480px) {
  .form-row {
    grid-template-columns: 1fr;
  }
  .hero h1 { font-size: 22px; }
  .result-highlight .value { font-size: 22px; }
}