/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --primary-light: #e8f0fe;
  --bg: #f8f9fa;
  --card-bg: #ffffff;
  --text: #202124;
  --text-secondary: #5f6368;
  --border: #dadce0;
  --success: #0d904f;
  --shadow: 0 1px 3px rgba(0,0,0,.12), 0 1px 2px rgba(0,0,0,.06);
  --shadow-lg: 0 4px 16px rgba(0,0,0,.1);
  --radius: 12px;
  --max-w: 720px;
  --transition: .2s ease;
}

html { scroll-behavior: smooth; }

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;
  display: flex;
  flex-direction: column;
}

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

/* ===== HEADER ===== */
.header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo span { color: var(--primary); }

nav { display: flex; gap: 4px; }

nav a {
  padding: 8px 14px;
  border-radius: 8px;
  font-size: .9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: background var(--transition), color var(--transition);
}

nav a:hover, nav a.active {
  background: var(--primary-light);
  color: var(--primary);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text);
  padding: 4px;
}

/* ===== HERO ===== */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, #4285f4 100%);
  color: #fff;
  text-align: center;
  padding: 56px 16px;
}

.hero h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.hero p {
  font-size: 1.1rem;
  opacity: .9;
  max-width: 560px;
  margin: 0 auto;
}

/* ===== MAIN ===== */
main {
  flex: 1;
  max-width: var(--max-w);
  width: 100%;
  margin: 0 auto;
  padding: 32px 16px 48px;
}

/* ===== CARD ===== */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 24px;
  margin-bottom: 24px;
}

.card h2 {
  font-size: 1.25rem;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--primary-light);
}

/* ===== TOOL CARDS (homepage) ===== */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}

.tool-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 24px;
  text-align: center;
  transition: box-shadow var(--transition), transform var(--transition);
}

.tool-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.tool-card .icon {
  width: 64px;
  height: 64px;
  border-radius: 16px;
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  margin: 0 auto 16px;
}

.tool-card h3 { font-size: 1.15rem; margin-bottom: 8px; }
.tool-card p { color: var(--text-secondary); font-size: .9rem; margin-bottom: 20px; }

.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 10px 28px;
  border-radius: 8px;
  font-weight: 600;
  font-size: .95rem;
  border: none;
  cursor: pointer;
  transition: background var(--transition);
}

.btn:hover { background: var(--primary-dark); color: #fff; }

/* ===== FORM ELEMENTS ===== */
.form-group { margin-bottom: 18px; }

.form-group label {
  display: block;
  font-weight: 600;
  font-size: .9rem;
  margin-bottom: 6px;
  color: var(--text);
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  color: var(--text);
  background: var(--card-bg);
  transition: border-color var(--transition);
  outline: none;
}

.form-group input:focus,
.form-group select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(26,115,232,.15);
}

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

.radio-group label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 400;
  padding: 8px 16px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition);
  flex: 1;
  justify-content: center;
  min-width: 100px;
}

.radio-group input[type="radio"] { display: none; }
.radio-group input[type="radio"]:checked + label,
.radio-group label.active {
  border-color: var(--primary);
  background: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
}

.calc-btn {
  width: 100%;
  padding: 14px;
  margin-top: 8px;
  font-size: 1.05rem;
}

/* ===== RESULTS ===== */
.result-box {
  background: #f0faf4;
  border: 1.5px solid #b7e4c7;
  border-radius: 10px;
  padding: 20px;
  margin-top: 20px;
  display: none;
}

.result-box.show { display: block; animation: fadeIn .3s ease; }

.result-row {
  display: flex;
  justify-content: space-between;
  padding: 8px 0;
  border-bottom: 1px solid #d4edda;
  font-size: .95rem;
}

.result-row:last-child { border-bottom: none; }
.result-row .label { color: var(--text-secondary); }
.result-row .value { font-weight: 700; color: var(--text); }

.result-row.total {
  border-top: 2px solid var(--success);
  border-bottom: none;
  margin-top: 4px;
  padding-top: 12px;
  font-size: 1.1rem;
}

.result-row.total .label { color: var(--success); font-weight: 600; }
.result-row.total .value { color: var(--success); font-size: 1.15rem; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

/* ===== AD PLACEHOLDER ===== */
.ad-slot {
  background: var(--card-bg);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  color: var(--text-secondary);
  font-size: .85rem;
  margin: 24px 0;
}

/* ===== SEO CONTENT ===== */
.seo-content {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 24px;
  margin-top: 24px;
}

.seo-content h2 {
  font-size: 1.2rem;
  margin-bottom: 12px;
  color: var(--text);
}

.seo-content p, .seo-content li {
  color: var(--text-secondary);
  font-size: .93rem;
  line-height: 1.7;
}

.seo-content ul { padding-left: 20px; margin: 8px 0; }
.seo-content li { margin-bottom: 4px; }

/* ===== FOOTER ===== */
footer {
  background: var(--card-bg);
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 24px 16px;
  color: var(--text-secondary);
  font-size: .85rem;
  margin-top: auto;
}

footer a { color: var(--text-secondary); margin: 0 10px; }
footer a:hover { color: var(--primary); }

.footer-links { margin-bottom: 8px; }

/* ===== STATIC PAGES ===== */
.static-page { max-width: var(--max-w); margin: 0 auto; padding: 32px 16px 48px; }
.static-page h1 { font-size: 1.5rem; margin-bottom: 20px; }
.static-page h2 { font-size: 1.15rem; margin: 20px 0 8px; }
.static-page p { color: var(--text-secondary); margin-bottom: 12px; line-height: 1.7; }

/* ===== RESPONSIVE ===== */
@media (max-width: 640px) {
  .menu-toggle { display: block; }

  nav {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--card-bg);
    flex-direction: column;
    padding: 8px 16px 16px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
  }

  nav.open { display: flex; }

  .hero h1 { font-size: 1.5rem; }
  .hero { padding: 40px 16px; }
  .card { padding: 20px 16px; }
  .result-row { font-size: .88rem; }
}