/* ===== CSS Variables & Reset ===== */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #dbeafe;
  --accent: #059669;
  --accent-light: #d1fae5;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #1e293b;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --radius: 12px;
  --radius-sm: 8px;
  --max-width: 1200px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

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

img { max-width: 100%; height: auto; }

/* ===== Header & Navigation ===== */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
  background: rgba(255,255,255,0.95);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo svg { width: 32px; height: 32px; }

nav { display: flex; gap: 8px; align-items: center; }

nav a {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: all 0.2s;
}

nav a:hover, nav a.active {
  background: var(--primary-light);
  color: var(--primary);
  text-decoration: none;
}

/* ===== Hero Section ===== */
.hero {
  background: linear-gradient(135deg, #1e40af 0%, #3b82f6 50%, #06b6d4 100%);
  color: white;
  padding: 80px 24px;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 16px;
  line-height: 1.2;
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto 32px;
}

.hero-cta {
  display: inline-flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s;
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: white;
  color: var(--primary);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.2);
  text-decoration: none;
}

.btn-secondary {
  background: rgba(255,255,255,0.15);
  color: white;
  border: 1px solid rgba(255,255,255,0.3);
}
.btn-secondary:hover {
  background: rgba(255,255,255,0.25);
  text-decoration: none;
}

/* ===== Container ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 64px 0; }
section h2 {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
}
section .section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 48px;
  font-size: 1.1rem;
}

/* ===== Tool Cards Grid ===== */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.tool-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: all 0.3s;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.tool-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: var(--primary-light);
}

.tool-card .icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.tool-card .icon.blue { background: var(--primary-light); color: var(--primary); }
.tool-card .icon.green { background: var(--accent-light); color: var(--accent); }
.tool-card .icon.orange { background: #fef3c7; color: #d97706; }
.tool-card .icon.purple { background: #ede9fe; color: #7c3aed; }
.tool-card .icon.red { background: #fee2e2; color: #dc2626; }
.tool-card .icon.teal { background: #ccfbf1; color: #0d9488; }

.tool-card h3 { font-size: 1.15rem; font-weight: 700; }
.tool-card p { color: var(--text-secondary); font-size: 0.95rem; flex: 1; }

.tool-card .card-link {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 4px;
}

/* ===== Calculator Page Styles ===== */
.calc-page { max-width: 800px; margin: 0 auto; padding: 48px 24px; }
.calc-page h1 { font-size: 2rem; margin-bottom: 4px; }
.calc-page .breadcrumb { color: var(--text-secondary); margin-bottom: 24px; font-size: 0.9rem; }

.calc-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-weight: 600; margin-bottom: 6px; font-size: 0.9rem; }
.form-group .input-row { display: flex; gap: 12px; align-items: center; }
.form-group input, .form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  transition: border 0.2s;
  background: var(--bg);
}
.form-group input:focus, .form-group select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.input-suffix {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9rem;
  min-width: 40px;
}

.btn-calc {
  width: 100%;
  padding: 14px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.btn-calc:hover { background: var(--primary-dark); }

.result {
  margin-top: 24px;
  padding: 20px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  display: none;
}
.result.show { display: block; }
.result h3 { color: var(--accent); margin-bottom: 8px; }
.result .big-number { font-size: 2.5rem; font-weight: 800; color: var(--accent); }
.result .detail { color: var(--text-secondary); font-size: 0.9rem; margin-top: 4px; }

.result-table { width: 100%; border-collapse: collapse; margin-top: 16px; }
.result-table th, .result-table td {
  padding: 10px 12px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}
.result-table th { font-weight: 600; background: var(--bg); }

/* ===== Blog ===== */
.blog-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 24px; }
.blog-card {
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: all 0.3s;
}
.blog-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-2px); }
.blog-card-body { padding: 24px; }
.blog-card .date { color: var(--text-secondary); font-size: 0.85rem; }
.blog-card h3 { margin: 8px 0; font-size: 1.1rem; }
.blog-card p { color: var(--text-secondary); font-size: 0.9rem; }

/* ===== Ad Placements ===== */
.ad-banner {
  background: var(--surface);
  border: 2px dashed var(--border);
  border-radius: var(--radius-sm);
  padding: 20px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin: 24px 0;
}
.ad-banner.inline { max-width: 728px; margin: 24px auto; }
.ad-banner.sidebar { min-height: 250px; display: flex; align-items: center; justify-content: center; }

/* ===== Affiliate Section ===== */
.affiliate-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin-top: 24px;
}
.affiliate-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px;
  transition: all 0.2s;
}
.affiliate-card:hover { border-color: var(--accent); }
.affiliate-card h4 { font-size: 1rem; margin-bottom: 4px; }
.affiliate-card .rating { color: #f59e0b; }
.affiliate-card p { font-size: 0.85rem; color: var(--text-secondary); margin: 8px 0; }
.affiliate-card .aff-link {
  display: inline-block;
  padding: 8px 16px;
  background: var(--accent);
  color: white;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 600;
}
.affiliate-card .aff-link:hover { text-decoration: none; opacity: 0.9; }

/* ===== Footer ===== */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 48px 24px 24px;
  margin-top: 64px;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 32px;
}
.footer-inner h4 { margin-bottom: 12px; font-size: 0.9rem; color: var(--text-secondary); text-transform: uppercase; }
.footer-inner a { display: block; font-size: 0.9rem; margin-bottom: 6px; color: var(--text); }
.footer-inner a:hover { color: var(--primary); text-decoration: none; }
.copyright {
  text-align: center;
  padding-top: 24px;
  margin-top: 24px;
  border-top: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .hero { padding: 48px 16px; }
  section { padding: 40px 0; }
  .tools-grid, .blog-grid, .affiliate-grid { grid-template-columns: 1fr; }
  nav { display: none; }
  .calc-card { padding: 20px; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.6rem; }
}