:root {
  /* PREMIUM LIGHT THEME */
  --bg: #f8fafc;
  --bg2: #ffffff;
  --bg3: #f1f5f9;
  --text: #0f172a;
  --text2: #334155;
  --text3: #64748b;
  --border: #e2e8f0;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-glow: rgba(79, 70, 229, 0.2);
  --accent: #10b981;
  --accent-hover: #059669;
  --accent-glow: rgba(16, 185, 129, 0.2);
  --danger: #ef4444;
  --radius: 16px;
  --radius-sm: 8px;
  --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
  --shadow-lg: 0 10px 25px -3px rgba(0,0,0,0.05), 0 4px 10px -2px rgba(0,0,0,0.02);
  --shadow-float: 0 20px 40px -10px rgba(0,0,0,0.1);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: 'JetBrains Mono', monospace;
  --glass-bg: rgba(255, 255, 255, 0.85);
  --card-border: 1px solid #e2e8f0;
}
[data-theme="dark"] {
  /* PREMIUM DARK THEME */
  --bg: #0b0f19;
  --bg2: #141a29;
  --bg3: #1e2536;
  --text: #f8fafc;
  --text2: #cbd5e1;
  --text3: #94a3b8;
  --border: #2a3346;
  --primary: #6366f1;
  --primary-hover: #818cf8;
  --primary-glow: rgba(99, 102, 241, 0.25);
  --accent: #10b981;
  --accent-hover: #34d399;
  --accent-glow: rgba(16, 185, 129, 0.25);
  --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4);
  --shadow-lg: 0 10px 25px -3px rgba(0,0,0,0.5);
  --shadow-float: 0 20px 40px -10px rgba(0,0,0,0.6);
  --glass-bg: rgba(20, 26, 41, 0.85);
  --card-border: 1px solid #2a3346;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

/* Subtle background pattern/mesh */
body::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 500px;
  background: radial-gradient(circle at 15% 50%, var(--primary-glow), transparent 40%),
              radial-gradient(circle at 85% 30%, var(--accent-glow), transparent 40%);
  z-index: -1; opacity: 0.6; pointer-events: none;
}

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

/* Header Glassmorphism */
.site-header {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}
.header-inner {
  max-width: 1300px; margin: 0 auto; padding: 0.8rem 2rem;
  display: flex; justify-content: space-between; align-items: center;
}
.logo {
  font-size: 1.3rem; font-weight: 800; letter-spacing: -0.5px;
  display: flex; align-items: center; gap: 8px; color: var(--text);
}
.logo-icon {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: white; width: 32px; height: 32px; border-radius: 8px;
  display: flex; justify-content: center; align-items: center; font-size: 0.9rem;
  box-shadow: 0 4px 12px var(--primary-glow);
}
.logo span { color: var(--text3); font-weight: 400; }
.nav-links { display: flex; gap: 20px; }
.nav-links a { color: var(--text2); font-weight: 500; font-size: 0.9rem; padding: 4px 8px; border-radius: 6px; }
.nav-links a:hover { background: var(--bg3); color: var(--text); }

/* Theme Toggle Button */
.btn-theme {
  background: var(--bg3); border: 1px solid var(--border);
  width: 36px; height: 36px; border-radius: 50%;
  cursor: pointer; font-size: 1.1rem;
  display: flex; justify-content: center; align-items: center;
  transition: all 0.2s; color: var(--text);
}
.btn-theme:hover { background: var(--border); transform: rotate(15deg); }

/* Hero Section */
.hero { text-align: center; padding: 4rem 2rem 3rem; max-width: 900px; margin: 0 auto; animation: fadeUp 0.6s ease-out; }
.hero-badge {
  display: inline-block; background: var(--primary-glow); color: var(--primary);
  padding: 6px 14px; border-radius: 20px; font-size: 0.8rem; font-weight: 700;
  margin-bottom: 1.5rem; border: 1px solid rgba(99, 102, 241, 0.3);
  text-transform: uppercase; letter-spacing: 0.5px;
}
.hero h1 { font-size: 3.5rem; font-weight: 800; line-height: 1.1; margin-bottom: 1rem; letter-spacing: -1px; }
.hero h1 em { font-style: normal; background: linear-gradient(to right, var(--primary), var(--accent)); -webkit-background-clip: text; color: transparent; }
.hero-sub { font-size: 1.15rem; color: var(--text2); max-width: 700px; margin: 0 auto 2rem; }
.hero-tags { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.hero-tags span { background: var(--bg2); border: var(--card-border); padding: 4px 12px; border-radius: 6px; font-size: 0.85rem; font-weight: 500; color: var(--text3); box-shadow: var(--shadow-sm); }

/* Main App Wrapper */
.main-wrap { max-width: 1300px; margin: 0 auto; padding: 0 2rem 4rem; width: 100%; animation: fadeUp 0.8s ease-out; }

/* The Converter Card */
.converter-card {
  background: var(--bg2);
  border-radius: var(--radius);
  border: var(--card-border);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  margin-bottom: 3rem;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.converter-card:hover { box-shadow: var(--shadow-float); }

/* Options Bar */
.options-bar {
  background: var(--bg3); border-bottom: var(--card-border);
  padding: 12px 20px; display: flex; gap: 16px; align-items: center; flex-wrap: wrap;
}
.opt-group { display: flex; align-items: center; gap: 8px; }
.opt-label { font-size: 0.8rem; font-weight: 600; color: var(--text2); text-transform: uppercase; letter-spacing: 0.5px; }
.opt-input, .opt-select {
  background: var(--bg2); border: 1px solid var(--border); color: var(--text);
  padding: 6px 12px; border-radius: 6px; font-size: 0.85rem;
  outline: none; transition: all 0.2s; font-family: var(--font-sans); font-weight: 500;
}
.opt-input:focus, .opt-select:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-glow); }
.opt-divider { width: 1px; height: 24px; background: var(--border); margin: 0 4px; }

/* MODERN TOGGLE SWITCHES (replaces basic checkboxes) */
.opt-check {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  font-size: 0.85rem; font-weight: 500; color: var(--text2);
}
.opt-check input[type="checkbox"] {
  appearance: none; -webkit-appearance: none;
  width: 36px; height: 20px; background: var(--border);
  border-radius: 20px; position: relative; outline: none;
  transition: background 0.3s, box-shadow 0.3s; cursor: pointer;
}
.opt-check input[type="checkbox"]::after {
  content: ''; position: absolute; top: 2px; left: 2px;
  width: 16px; height: 16px; background: #fff; border-radius: 50%;
  transition: transform 0.3s cubic-bezier(0.4, 0.0, 0.2, 1);
  box-shadow: 0 1px 3px rgba(0,0,0,0.3);
}
.opt-check input[type="checkbox"]:checked { background: var(--primary); }
.opt-check input[type="checkbox"]:checked::after { transform: translateX(16px); }
.opt-check input[type="checkbox"]:focus-visible { box-shadow: 0 0 0 3px var(--primary-glow); }

/* URL Bar overrides */
input[type="url"] { transition: border-color 0.2s, box-shadow 0.2s; }
input[type="url"]:focus { border-color: var(--primary)!important; box-shadow: 0 0 0 3px var(--primary-glow)!important; outline:none; }

/* Panels */
.panels { display: flex; flex-direction: column; }
@media (min-width: 900px) { .panels { flex-direction: row; } .panel { width: 50%; } .panel:first-child { border-right: var(--card-border); } }
.panel { display: flex; flex-direction: column; background: var(--bg2); }
.panel-header {
  padding: 12px 20px; border-bottom: var(--card-border);
  display: flex; justify-content: space-between; align-items: center; background: rgba(0,0,0,0.01);
}
.panel-title { font-weight: 700; font-size: 0.9rem; color: var(--text); letter-spacing: 0.5px; }
.panel-actions { display: flex; gap: 8px; }

/* Editor Areas */
.editor-wrap { position: relative; flex: 1; min-height: 400px; display: flex; background: var(--bg2); }
.code-area {
  width: 100%; height: 100%; min-height: 400px; padding: 16px;
  border: none; background: transparent; color: var(--text);
  font-family: var(--mono); font-size: 13.5px; line-height: 1.5;
  resize: vertical; outline: none; white-space: pre; overflow: auto;
}
.code-area::placeholder { color: var(--text3); opacity: 0.6; }

/* Drag & Drop Overlay */
.drop-zone {
  position: absolute; inset: 0; background: var(--primary-glow);
  backdrop-filter: blur(4px); display: flex; flex-direction: column;
  justify-content: center; align-items: center; z-index: 10;
  opacity: 0; pointer-events: none; transition: opacity 0.2s; border: 2px dashed var(--primary);
}
.drop-zone.visible { opacity: 1; }
.drop-zone-icon { font-size: 3rem; margin-bottom: 10px; }

/* File Upload Hidden Input */
.file-upload-label {
  display: inline-block; background: var(--bg3); border: 1px solid var(--border);
  padding: 4px 10px; border-radius: 6px; font-size: 0.8rem; font-weight: 600;
  cursor: pointer; transition: all 0.2s; color: var(--text2);
}
.file-upload-label:hover { background: var(--border); color: var(--text); }
input[type="file"] { display: none; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 8px 16px; border-radius: 8px; font-size: 0.9rem; font-weight: 600;
  cursor: pointer; border: none; transition: all 0.2s; font-family: var(--font-sans);
}
.btn:active { transform: scale(0.97); }
.btn:disabled { opacity: 0.6; cursor: not-allowed; transform: none; }
.btn-sm { padding: 4px 10px; font-size: 0.8rem; border-radius: 6px; }

.btn-primary { background: linear-gradient(to right, var(--primary), var(--primary-hover)); color: #fff; box-shadow: 0 4px 12px var(--primary-glow); }
.btn-primary:hover:not(:disabled) { box-shadow: 0 6px 16px var(--primary-glow); transform: translateY(-1px); }

.btn-accent { background: linear-gradient(to right, var(--accent), var(--accent-hover)); color: #fff; box-shadow: 0 4px 12px var(--accent-glow); }
.btn-accent:hover:not(:disabled) { box-shadow: 0 6px 16px var(--accent-glow); transform: translateY(-1px); }

.btn-secondary { background: var(--bg3); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover:not(:disabled) { background: var(--border); }

/* Action Bar */
.action-bar { padding: 16px 20px; border-top: var(--card-border); background: var(--bg3); display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.status-msg { margin-left: auto; font-size: 0.85rem; font-weight: 600; color: var(--text3); display: flex; align-items: center; gap: 6px; }
.status-msg.ok { color: var(--accent); }
.status-msg.err { color: var(--danger); }

/* Spinner */
.spinner {
  display: none; width: 14px; height: 14px; border: 2px solid rgba(255,255,255,0.3);
  border-radius: 50%; border-top-color: #fff; animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
@keyframes fadeUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }

/* Stats Bar */
.stats-bar {
  padding: 8px 20px; background: var(--bg2); border-top: var(--card-border);
  display: none; gap: 20px; font-size: 0.8rem; color: var(--text3); font-family: var(--mono);
}
.stats-bar.show, .stats-bar[style*="display: flex"] { display: flex; }
.stats-bar b { color: var(--text); font-weight: 600; }

/* Table Preview / UI DataTables */
.preview-section { display: none; padding: 20px; border-top: var(--card-border); background: var(--bg); }
.preview-section.visible { display: block; animation: fadeUp 0.4s ease; }
.preview-header { display: flex; justify-content: space-between; margin-bottom: 12px; }
.preview-header h2 { font-size: 1.1rem; }
.table-wrap { overflow-x: auto; max-height: 400px; border: var(--card-border); border-radius: var(--radius-sm); background: var(--bg2); box-shadow: var(--shadow-sm); }
table { width: 100%; border-collapse: collapse; text-align: left; font-size: 0.85rem; }
th { background: var(--bg3); padding: 10px 12px; font-weight: 600; color: var(--text2); border-bottom: var(--card-border); position: sticky; top: 0; z-index: 1; }
td { padding: 8px 12px; border-bottom: var(--card-border); color: var(--text); white-space: nowrap; max-width: 300px; overflow: hidden; text-overflow: ellipsis; }
tr:hover td { background: var(--bg3); }

/* Custom Search Input in tables */
#tableSearch {
  background: var(--bg2); border: 1px solid var(--border); color: var(--text);
  padding: 8px 14px; border-radius: 20px; font-size: 0.9rem; width: 100%; max-width: 300px;
  outline: none; transition: all 0.2s; box-shadow: var(--shadow-sm);
}
#tableSearch:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-glow); }

/* Tool Grid (Homepage & Related) */
.related-tools { margin-top: 2rem; }
.related-tools h2 { font-size: 1.5rem; margin-bottom: 1.5rem; font-weight: 800; text-align: center; }
.related-grid, .tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; }
.related-card, .tool-card {
  background: var(--bg2); border: var(--card-border); border-radius: 12px;
  padding: 16px; display: flex; align-items: center; gap: 16px;
  transition: all 0.3s; box-shadow: var(--shadow-sm); cursor: pointer; text-decoration: none;
}
.related-card:hover, .tool-card:hover {
  transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: var(--primary);
}
.related-card-icon, .tool-card-icon {
  width: 48px; height: 48px; background: var(--bg3); border-radius: 10px;
  display: flex; justify-content: center; align-items: center; font-size: 1.5rem;
}
.related-card-text strong, .tool-card-text strong { display: block; color: var(--text); font-size: 1rem; margin-bottom: 4px; }
.related-card-text span, .tool-card-text span { color: var(--text3); font-size: 0.8rem; }

/* Article & Content */
.content-section, .article-section { max-width: 900px; margin: 4rem auto; padding: 0 2rem; }
.article-section h2, .content-section h2 { font-size: 1.8rem; margin-bottom: 1rem; font-weight: 800; letter-spacing: -0.5px; }
.article-section h3 { font-size: 1.3rem; margin: 1.5rem 0 0.5rem; }
.article-section p { margin-bottom: 1rem; color: var(--text2); font-size: 1.05rem; }
.article-section ul, .article-section ol { margin-bottom: 1rem; padding-left: 1.5rem; color: var(--text2); }
.article-section li { margin-bottom: 0.5rem; }
.article-section code { background: var(--bg3); padding: 2px 6px; border-radius: 4px; font-family: var(--mono); font-size: 0.9em; color: var(--primary); }
.article-section pre { background: var(--bg2); border: var(--card-border); padding: 16px; border-radius: 8px; overflow-x: auto; margin-bottom: 1.5rem; font-family: var(--mono); font-size: 0.9rem; }

/* FAQ Details */
.faq-grid { display: grid; gap: 12px; }
details { background: var(--bg2); border: var(--card-border); border-radius: 12px; padding: 16px; cursor: pointer; transition: all 0.2s; box-shadow: var(--shadow-sm); }
details:hover { border-color: var(--primary); }
summary { font-weight: 700; font-size: 1.05rem; list-style: none; display: flex; justify-content: space-between; align-items: center; outline: none; }
summary::-webkit-details-marker { display: none; }
summary::after { content: '+'; font-size: 1.5rem; color: var(--primary); transition: transform 0.3s; }
details[open] summary::after { transform: rotate(45deg); }
details p { margin-top: 12px; color: var(--text2); font-size: 0.95rem; line-height: 1.6; padding-top: 12px; border-top: 1px dashed var(--border); }

/* Footer */
footer { background: var(--bg2); border-top: var(--card-border); padding: 3rem 2rem; margin-top: auto; }
.footer-inner { max-width: 1300px; margin: 0 auto; display: flex; flex-direction: column; align-items: center; gap: 1.5rem; }
.footer-brand { font-weight: 800; font-size: 1.2rem; }
.footer-links { display: flex; gap: 1.5rem; flex-wrap: wrap; justify-content: center; }
.footer-links a { color: var(--text2); font-size: 0.9rem; }
.footer-copy { color: var(--text3); font-size: 0.85rem; }

/* Toast */
.toast {
  position: fixed; bottom: 24px; right: 24px; background: var(--text); color: var(--bg);
  padding: 12px 24px; border-radius: 8px; font-weight: 600; font-size: 0.9rem;
  transform: translateY(100px); opacity: 0; transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 1000; box-shadow: var(--shadow-lg); pointer-events: none;
}
.toast.show { transform: translateY(0); opacity: 1; }
.toast.err { background: var(--danger); color: white; }
.toast.ok { background: var(--accent); color: white; }

/* Scrollbars */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text3); }

/* Accessibility */
.skip-link { position: absolute; top: -40px; left: 0; background: var(--primary); color: white; padding: 8px; z-index: 1000; transition: top 0.2s; }
.skip-link:focus { top: 0; }
:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }