/* Base Variables */
:root {
  --bg-color: #ffffff;
  --text-color: #111827;
  --text-muted: #6b7280;
  --card-bg: #f3f4f6;
  --border-color: #e5e7eb;
  --accent-color: #10b981;
  --accent-hover: #059669;
  --input-bg: #ffffff;
}

[data-theme='dark'] {
  --bg-color: #0f1117;
  --text-color: #f9fafb;
  --text-muted: #9ca3af;
  --card-bg: #1a1b23;
  --border-color: #374151;
  --input-bg: #111827;
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.5;
  transition: background-color 0.2s, color 0.2s;
}

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

a:hover {
  text-decoration: underline;
}

/* Layout */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  border-bottom: 1px solid var(--border-color);
  padding: 15px 0;
  background-color: var(--card-bg);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-color);
}
.logo:hover {
  text-decoration: none;
}

/* Buttons */
.btn {
  background-color: transparent;
  color: var(--text-color);
  border: 1px solid var(--border-color);
  padding: 8px 16px;
  cursor: pointer;
  font-family: inherit;
  font-weight: 500;
  transition: all 0.2s;
}

.btn:hover {
  background-color: var(--border-color);
}

/* Cards */
.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  padding: 20px;
  margin-bottom: 20px;
}

/* Hero & Search (Homepage) */
.hero {
  text-align: center;
  padding: 50px 20px;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 10px;
}

.hero p {
  color: var(--text-muted);
  font-size: 1.1rem;
  margin-bottom: 30px;
}

.search-box {
  width: 100%;
  max-width: 600px;
  padding: 15px;
  font-size: 1.1rem;
  background-color: var(--input-bg);
  color: var(--text-color);
  border: 1px solid var(--border-color);
  font-family: inherit;
}
.search-box:focus {
  outline: 2px solid var(--accent-color);
  border-color: transparent;
}

/* Category Grid */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin-bottom: 40px;
}

.category-card h2 {
  font-size: 1.25rem;
  margin-bottom: 15px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.converter-list {
  list-style: none;
}

.converter-list li {
  margin-bottom: 8px;
}

/* Converter Page Layout */
.page-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 30px;
  margin-top: 30px;
  margin-bottom: 50px;
}

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

.breadcrumb {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.main-content h1 {
  font-size: 2rem;
  margin-bottom: 25px;
}

/* Converter UI */
.converter-card {
  display: flex;
  align-items: center;
  gap: 15px;
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  padding: 30px;
  margin-bottom: 30px;
}

@media (max-width: 600px) {
  .converter-card {
    flex-direction: column;
  }
}

.input-group {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.input-group label {
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--text-muted);
}

.input-group input {
  width: 100%;
  font-size: 2rem;
  padding: 15px;
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  color: var(--text-color);
  font-family: inherit;
}

.input-group input:focus {
  outline: 2px solid var(--accent-color);
  border-color: transparent;
}

.equals {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-muted);
}

/* Formula & Table Section */
.formula-section h2, .table-section h2 {
  font-size: 1.25rem;
  margin-bottom: 15px;
}

.formula {
  font-family: 'JetBrains Mono', monospace;
  background-color: var(--input-bg);
  padding: 10px;
  border: 1px solid var(--border-color);
  margin-top: 10px;
  display: inline-block;
}

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

th, td {
  padding: 12px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

th {
  font-weight: 600;
  background-color: var(--input-bg);
}

/* Sidebar */
.related-card ul {
  list-style: none;
}
.related-card ul li {
  margin-bottom: 8px;
}

/* Ad Slots */
.ad-slot {
  background-color: var(--card-bg);
  border: 1px dashed var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 30px;
}

.ad-slot-header {
  height: 90px;
  margin-top: 20px;
  margin-bottom: 20px;
}

.ad-slot-content {
  height: 280px;
}

.ad-slot-sidebar {
  height: 250px;
}

/* Footer */
footer {
  border-top: 1px solid var(--border-color);
  padding: 30px 0;
  text-align: center;
  color: var(--text-muted);
  background-color: var(--card-bg);
}