/* ToolVibe Modern Premium Design System */
:root {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: rgba(30, 41, 59, 0.7);
  --bg-card-hover: rgba(51, 65, 85, 0.8);
  --border-color: rgba(255, 255, 255, 0.1);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-color: #38bdf8;
  --accent-hover: #0284c7;
  --accent-gradient: linear-gradient(135deg, #38bdf8 0%, #818cf8 100%);
  --success-color: #4ade80;
  --warning-color: #facc15;
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.25);
  --shadow-glow: 0 0 20px rgba(56, 189, 248, 0.2);
  --font-sans: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --border-color: #e2e8f0;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --accent-color: #0284c7;
  --accent-hover: #0369a1;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-hover);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  width: 100%;
}

/* Header & Navbar */
.site-header {
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 16px 0;
}

[data-theme="light"] .site-header {
  background: rgba(255, 255, 255, 0.9);
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-primary);
}

.brand-badge {
  background: var(--accent-gradient);
  color: #fff;
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 20px;
  font-weight: 600;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s ease;
}

.nav-link:hover, .nav-link.active {
  color: var(--accent-color);
}

.theme-toggle {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
}

/* Hero Section */
.hero-section {
  padding: 60px 0 40px;
  text-align: center;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 16px;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 32px;
}

/* Tool Tabs & Box */
.tool-section {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  margin-bottom: 60px;
}

.tool-tabs {
  display: flex;
  gap: 12px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 16px;
  margin-bottom: 28px;
  overflow-x: auto;
}

.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s ease;
}

.tab-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
}

.tab-btn.active {
  background: var(--accent-gradient);
  color: #ffffff;
  box-shadow: var(--shadow-glow);
}

.tool-panel {
  display: none;
}

.tool-panel.active {
  display: block;
}

/* Forms & Inputs */
.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.form-control, .form-textarea {
  width: 100%;
  padding: 14px 16px;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1rem;
  transition: border-color 0.2s ease;
}

.form-control:focus, .form-textarea:focus {
  outline: none;
  border-color: var(--accent-color);
}

.form-textarea {
  min-height: 180px;
  resize: vertical;
}

.btn-primary {
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-primary:hover {
  opacity: 0.9;
}

.btn-secondary {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
}

/* Tool Grid / Results */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.stat-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  padding: 16px;
  border-radius: var(--radius-sm);
  text-align: center;
}

.stat-value {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--accent-color);
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-top: 4px;
}

/* Post Cards Grid */
.section-title {
  font-size: 1.8rem;
  font-weight: 800;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
  margin-bottom: 60px;
}

.post-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.post-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-color);
}

.post-category {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-color);
  text-transform: uppercase;
  margin-bottom: 8px;
}

.post-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
  line-height: 1.4;
}

.post-excerpt {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
  flex-grow: 1;
}

.post-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 12px;
}

/* Post Detail Page */
.post-detail {
  max-width: 800px;
  margin: 40px auto 80px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 40px;
}

.post-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 24px;
  margin-bottom: 32px;
}

.post-content {
  line-height: 1.8;
  font-size: 1.05rem;
}

.post-content h2 {
  font-size: 1.5rem;
  margin: 32px 0 16px;
  color: var(--text-primary);
  border-left: 4px solid var(--accent-color);
  padding-left: 12px;
}

.post-content h3 {
  font-size: 1.25rem;
  margin: 24px 0 12px;
  color: var(--text-primary);
}

.post-content p {
  margin-bottom: 18px;
  color: var(--text-secondary);
}

.post-content ul, .post-content ol {
  margin: 0 0 20px 24px;
  color: var(--text-secondary);
}

.post-content li {
  margin-bottom: 8px;
}

.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
}

.post-content th, .post-content td {
  border: 1px solid var(--border-color);
  padding: 12px 16px;
  text-align: left;
}

.post-content th {
  background: var(--bg-primary);
  color: var(--text-primary);
  font-weight: 700;
}

.faq-box {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 20px;
  margin: 24px 0;
}

.faq-q {
  font-weight: 700;
  color: var(--accent-color);
  margin-bottom: 8px;
}

.faq-a {
  color: var(--text-secondary);
}

/* Footer */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 40px 0 24px;
  margin-top: auto;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 32px;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 12px;
  max-width: 360px;
}

.footer-title {
  font-weight: 700;
  margin-bottom: 16px;
  font-size: 1rem;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: var(--accent-color);
}

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 24px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Responsive */
@media (max-width: 768px) {
  .hero-title { font-size: 1.8rem; }
  .footer-content { grid-template-columns: 1fr; gap: 24px; }
  .tool-section { padding: 20px; }
  .post-detail { padding: 24px; }
  .nav-wrapper { flex-direction: column; gap: 16px; align-items: flex-start; }
  .main-nav { width: 100%; justify-content: space-between; overflow-x: auto; }
}