:root {
  --bg: #f1f5f9;
  --card-bg: #fff;
  --text: #1e293b;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --border: #e2e8f0;
  --accent: #3b82f6;
  --accent-bg: #eff6ff;
  --accent-dark: #2563eb;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-lg: 0 4px 24px rgba(0,0,0,0.08);
  --radius: 16px;
  --hero-start: #0f172a;
  --hero-end: #1e40af;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --card-bg: #1e293b;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --text-light: #64748b;
  --border: #334155;
  --accent: #60a5fa;
  --accent-bg: #1e3a5f;
  --accent-dark: #3b82f6;
  --shadow: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-lg: 0 4px 24px rgba(0,0,0,0.4);
  --hero-start: #020617;
  --hero-end: #1e3a5f;
}

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

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background 0.2s, color 0.2s;
}

a { text-decoration: none; color: inherit; }

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
  background: rgba(255,255,255,0.85);
}
[data-theme="dark"] .header {
  background: rgba(30,41,59,0.85);
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
}
.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--accent);
  color: white;
  border-radius: 10px;
  font-size: 18px;
}
.header-actions { display: flex; align-items: center; gap: 8px; }
.lang-toggle {
  display: flex;
  align-items: center;
  padding: 6px 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.15s;
  font-size: 14px;
  gap: 4px;
}
.lang-toggle:hover { background: var(--border); }
.lang-toggle .lang-sep { color: var(--text-light); font-size: 12px; }
.theme-toggle {
  display: flex;
  align-items: center;
  padding: 6px 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.15s;
}
.theme-toggle:hover { background: var(--border); box-shadow: 0 0 0 2px var(--accent-bg); }
.theme-toggle .sun { display: block; }
.theme-toggle .moon { display: none; }
[data-theme="dark"] .theme-toggle .sun { display: none; }
[data-theme="dark"] .theme-toggle .moon { display: block; }

/* Hero */
.hero {
  position: relative;
  padding: 80px 24px;
  text-align: center;
  overflow: hidden;
  background: linear-gradient(135deg, var(--hero-start), var(--hero-end));
  color: white;
}
.hero-content {
  position: relative;
  z-index: 1;
  max-width: 700px;
  margin: 0 auto;
}
.hero h1 {
  font-size: clamp(32px, 6vw, 52px);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}
.hero .highlight {
  background: linear-gradient(135deg, #60a5fa, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-sub {
  font-size: 18px;
  color: rgba(255,255,255,0.75);
  margin-bottom: 32px;
  line-height: 1.5;
}
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
}
.stat { text-align: center; }
.stat-num {
  display: block;
  font-size: 28px;
  font-weight: 800;
  color: #60a5fa;
}
.stat-label {
  font-size: 13px;
  color: rgba(255,255,255,0.6);
  margin-top: 4px;
}

/* Sections */
.section-header {
  text-align: center;
  padding: 60px 24px 8px;
}
.section-header h2 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
}
.section-header p {
  font-size: 15px;
  color: var(--text-muted);
}

/* Category filters */
.cat-filters {
  display: flex;
  justify-content: center;
  gap: 6px;
  padding: 24px 24px 0;
  flex-wrap: wrap;
}
.cat-filter {
  padding: 8px 20px;
  border: 1.5px solid var(--border);
  border-radius: 100px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  background: var(--card-bg);
  cursor: pointer;
  transition: all 0.15s;
}
.cat-filter:hover { border-color: var(--accent); color: var(--accent); }
.cat-filter.active { background: var(--accent); color: white; border-color: var(--accent); }

/* Tool search */
.tool-search {
  max-width: 400px;
  margin: 16px auto 0;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--card-bg);
  border: 1.5px solid var(--border);
  border-radius: 100px;
  padding: 8px 16px;
  transition: all 0.2s;
}
.tool-search:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-bg); }
.tool-search svg { color: var(--text-light); flex-shrink: 0; }
.tool-search-input {
  border: none;
  background: transparent;
  color: var(--text);
  font-size: 14px;
  width: 100%;
  outline: none;
  font-family: inherit;
}

/* Tools grid */
.tools-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}
.tool-card {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: all 0.2s;
  cursor: pointer;
}
.tool-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px) scale(1.01);
}
.tool-card:active { transform: translateY(-1px); }
.tool-card .card-body h3 { transition: color 0.15s; }
.tool-card:hover .card-body h3 { color: var(--accent); }
.card-icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  font-size: 11px;
  font-weight: 800;
  color: white;
}
.card-icon--jpg { background: linear-gradient(135deg, #f97316, #ef4444); }
.card-icon--png { background: linear-gradient(135deg, #3b82f6, #6366f1); }
.card-icon--webp { background: linear-gradient(135deg, #06b6d4, #0891b2); }
.card-icon--gif { background: linear-gradient(135deg, #8b5cf6, #a855f7); }
.card-icon--svg { background: linear-gradient(135deg, #f59e0b, #d97706); }
.card-icon--heic { background: linear-gradient(135deg, #10b981, #059669); }
.card-icon--pdf { background: linear-gradient(135deg, #ef4444, #dc2626); }
.card-icon--txt { background: linear-gradient(135deg, #64748b, #475569); }
.card-icon--docx { background: linear-gradient(135deg, #2563eb, #1d4ed8); }
.card-icon--md { background: linear-gradient(135deg, #f97316, #ea580c); }
.card-icon--ocr { background: linear-gradient(135deg, #14b8a6, #0d9488); }
.card-icon--merge { background: linear-gradient(135deg, #2563eb, #7c3aed); }
.card-icon--split { background: linear-gradient(135deg, #7c3aed, #db2777); }
.card-icon--url { background: linear-gradient(135deg, #0ea5e9, #0284c7); }
.card-icon--video { background: linear-gradient(135deg, #ec4899, #be185d); }
.card-icon--qr { background: linear-gradient(135deg, #1e293b, #334155); }
.card-icon--color { background: linear-gradient(135deg, #f97316, #ec4899); }

.card-body h3 {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text);
}
.card-body p {
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.4;
}

/* How it works */
.how-it-works {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 24px 60px;
}
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 32px;
}
.step-card {
  text-align: center;
  padding: 36px 24px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  position: relative;
}
.step-num {
  position: absolute;
  top: -12px;
  inset-inline-start: 50%;
  transform: translateX(-50%);
  width: 28px;
  height: 28px;
  background: var(--accent);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
}
.step-icon {
  color: var(--accent);
  margin-bottom: 12px;
}
.step-card { transition: all 0.2s; }
.step-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.step-card h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}
.step-card p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Footer */
.footer {
  text-align: center;
  padding: 32px 24px;
  font-size: 13px;
  color: var(--text-light);
  border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
  .header-inner { padding: 12px 16px; }
  .cat-filters { padding: 16px 12px 0; gap: 4px; }
  .cat-filter { font-size: 12px; padding: 6px 14px; }
  .tool-search { margin: 12px 12px 0; }
}
@media (max-width: 640px) {
  .hero { padding: 48px 20px; }
  .hero-stats { gap: 24px; }
  .stat-num { font-size: 22px; }
  .tools-grid { grid-template-columns: 1fr; padding: 16px; gap: 10px; }
  .tool-card { padding: 14px; }
  .steps { grid-template-columns: 1fr; gap: 24px; }
  .section-header { padding-top: 40px; }
  .section-header h2 { font-size: 22px; }
  .hero h1 { font-size: clamp(26px, 8vw, 36px); }
}