:root {
    --bg-primary: #0f1117;
    --bg-secondary: #161822;
    --bg-card: #1a1d28;
    --bg-elevated: #1e2230;
    --bg-input: #1a1d28;
    --text-primary: #e8eaed;
    --text-secondary: #9aa0b0;
    --text-muted: #6b7280;
    --border: #2a2d3a;
    --border-light: #333750;
    --accent: #4a90d9;
    --accent-hover: #5ba0e9;
    --accent-glow: rgba(74,144,217,0.2);
    --success: #34d399;
    --warning: #fbbf24;
    --danger: #ef4444;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
    --transition: 0.2s ease;
}

[data-theme="light"] {
    --bg-primary: #f8f9fc;
    --bg-secondary: #f0f2f7;
    --bg-card: #ffffff;
    --bg-elevated: #ffffff;
    --bg-input: #ffffff;
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --border: #e2e8f0;
    --border-light: #d0d7e2;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    margin: 0;
    -webkit-font-smoothing: antialiased;
}

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

h1, h2, h3, h4, h5, h6 { color: var(--text-primary); font-weight: 600; line-height: 1.3; }
p { color: var(--text-secondary); line-height: 1.7; }

.tool-h1 { color: var(--text-primary); font-size: 1.4rem; font-weight: 600; margin-bottom: 4px; }
.tool-desc { color: var(--text-muted); font-size: 0.85rem; margin-bottom: 16px; }
.tool-subtitle { color: var(--text-secondary); font-size: 0.95rem; margin-bottom: 8px; font-weight: 600; }
.tool-text { color: var(--text-secondary); font-size: 0.82rem; line-height: 1.7; }
.accent-icon { color: var(--accent) !important; }
.tool-info-card { margin-top: 24px; padding: 20px 24px; background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-md); transition: all var(--transition); }
.tool-info-card:hover { border-color: var(--border-light); box-shadow: var(--shadow-md); }

.navbar {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    padding: 0 1rem;
    min-height: 56px;
    box-shadow: var(--shadow-sm);
    z-index: 1030;
    position: sticky;
    top: 0;
}
.navbar-brand {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-primary) !important;
    letter-spacing: -0.3px;
}
.navbar-brand i { color: var(--accent); margin-right: 8px; font-size: 1.15rem; }
.navbar .badge-version {
    font-size: 0.6rem;
    background: var(--accent);
    color: #fff;
    padding: 2px 7px;
    border-radius: 20px;
    font-weight: 600;
    vertical-align: middle;
    margin-left: 4px;
    letter-spacing: 0.3px;
}
.navbar .nav-link-custom { color: var(--text-secondary); text-decoration: none; padding: 4px 6px; border-radius: var(--radius-sm); transition: all var(--transition); }
.navbar .nav-link-custom:hover { color: var(--text-primary); background: rgba(255,255,255,0.05); }
[data-theme="light"] .navbar .nav-link-custom:hover { background: rgba(0,0,0,0.04); }

.dropdown-menu {
    border: 1px solid var(--border) !important;
    box-shadow: var(--shadow-lg);
    border-radius: var(--radius-md);
    padding: 6px;
}
.dropdown-item { border-radius: var(--radius-sm); padding: 8px 12px; font-size: 0.88rem; transition: background var(--transition); }

.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    transition: all var(--transition);
}
.card:hover { border-color: var(--border-light); box-shadow: var(--shadow-md); }
.card.bg-dark { background: var(--bg-card) !important; border-color: var(--border) !important; }

.btn {
    border-radius: var(--radius-sm);
    font-weight: 500;
    padding: 8px 16px;
    transition: all var(--transition);
}
.btn-outline-secondary {
    color: var(--text-secondary) !important;
    border-color: var(--border) !important;
    background: var(--bg-elevated);
}
.btn-outline-secondary:hover {
    color: var(--text-primary) !important;
    background: var(--border) !important;
    border-color: var(--border-light) !important;
    transform: translateY(-1px);
}
.btn-outline-primary {
    color: var(--accent) !important;
    border-color: var(--accent) !important;
}
.btn-outline-primary:hover {
    background: var(--accent-glow) !important;
    color: #fff !important;
    transform: translateY(-1px);
}

.form-control, .form-select {
    background: var(--bg-input) !important;
    border: 1px solid var(--border) !important;
    color: var(--text-primary) !important;
    border-radius: var(--radius-sm);
}
.form-control:focus, .form-select:focus {
    border-color: var(--accent) !important;
    box-shadow: 0 0 0 3px var(--accent-glow) !important;
}

.form-check-input { border-color: var(--border-light); }
.form-check-input:checked { background-color: var(--accent); border-color: var(--accent); }

.site-footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 32px 0 0;
    margin-top: auto;
}
.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 28px;
}
.footer-col h4 { font-size: 0.85rem; color: var(--text-primary); margin-bottom: 12px; font-weight: 600; letter-spacing: 0.3px; }
.footer-col p { font-size: 0.82rem; color: var(--text-secondary); line-height: 1.6; }
.footer-col ul { list-style: none; padding: 0; margin: 0; }
.footer-col ul li { margin-bottom: 6px; }
.footer-col ul li a { color: var(--text-muted); font-size: 0.82rem; text-decoration: none; transition: color var(--transition); }
.footer-col ul li a:hover { color: var(--text-primary); }
.footer-bottom {
    border-top: 1px solid var(--border);
    padding: 16px 20px;
    margin-top: 28px;
    text-align: center;
    font-size: 0.78rem;
    color: var(--text-muted);
}
.footer-bottom a { color: var(--text-secondary); }

.toolbar-container {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 8px 12px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
    margin-bottom: 16px;
}
.toolbar-container .btn { font-size: 0.82rem; padding: 6px 12px; border-radius: 6px; }
.btn-run { background: var(--accent); color: #fff; border: none; font-weight: 600; }
.btn-run:hover { background: var(--accent-hover); box-shadow: 0 4px 14px var(--accent-glow); }
.btn-tool { background: var(--bg-elevated); color: var(--text-secondary); border: 1px solid var(--border); }
.btn-tool:hover { background: var(--border); color: var(--text-primary); }
.btn-tool.active-toggle.on { background: rgba(52,211,153,0.15); border-color: var(--success); color: var(--success); }
.toolbar-divider { width: 1px; height: 20px; background: var(--border); margin: 0 4px; }
.template-select {
    background: var(--bg-elevated);
    color: var(--text-primary);
    border: 1px solid var(--border);
    font-size: 0.82rem;
    padding: 6px 28px 6px 10px;
    border-radius: 6px;
    cursor: pointer;
}

.page-heading {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    padding: 16px 20px 0;
    margin: 0;
}

.editor-preview-row {
    display: flex;
    flex: 1;
    gap: 12px;
    padding: 12px 20px 20px;
    min-height: 0;
}
.editor-preview-row .panel { flex: 1; min-width: 0; }
@media (max-width: 991px) {
    .editor-preview-row { flex-direction: column; }
}

.panel {
    display: flex;
    flex-direction: column;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--border);
    background: var(--bg-secondary);
}
.panel-header {
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    padding: 10px 14px;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.editor-body { display: flex; flex: 1; min-height: 400px; }
.CodeMirror { flex: 1; border: none !important; border-radius: 0 !important; font-size: 14px; }

.preview-wrapper { display: flex; flex: 1; min-height: 0; }
.preview-frame { border: none !important; flex: 1; background: #fff; border-radius: 0 !important; }

.status-bar {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 6px 20px;
    font-size: 0.72rem;
    color: var(--text-muted);
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 16px;
}
.status-dot { width: 6px; height: 6px; border-radius: 50%; display: inline-block; }
.status-dot.synced { background: var(--success); box-shadow: 0 0 6px rgba(52,211,153,0.5); }
.status-dot.unsaved { background: var(--warning); }

.faq-section {
    background: var(--bg-secondary);
    padding: 48px 20px;
}
.faq-container { max-width: 760px; margin: 0 auto; }
.faq-title { font-size: 1.3rem; font-weight: 700; margin-bottom: 24px; color: var(--text-primary); display: flex; align-items: center; gap: 10px; }
.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    margin-bottom: 10px;
    overflow: hidden;
    transition: border-color var(--transition);
}
.faq-item:hover { border-color: var(--border-light); }
.faq-question {
    width: 100%;
    padding: 16px 20px;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 0.92rem;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background var(--transition);
}
.faq-question:hover { background: rgba(255,255,255,0.03); }
.faq-icon { font-size: 0.75rem; color: var(--accent); transition: transform var(--transition); }
.faq-question.open .faq-icon { transform: rotate(90deg); }
.faq-answer {
    padding: 0 20px 16px;
    color: var(--text-secondary);
    font-size: 0.88rem;
    line-height: 1.7;
}
.faq-answer:not(.open) { display: none; }

.guide-section {
    padding: 48px 20px;
    background: var(--bg-primary);
}
.guide-container { max-width: 900px; margin: 0 auto; }
.guide-container h2 { font-size: 1.3rem; font-weight: 700; margin-bottom: 24px; display: flex; align-items: center; gap: 10px; }
.guide-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.guide-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px;
    transition: all var(--transition);
}
.guide-card:hover { border-color: var(--border-light); transform: translateY(-2px); box-shadow: var(--shadow-md); }
.guide-card .card-icon { font-size: 1.8rem; color: var(--accent); margin-bottom: 12px; }
.guide-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 8px; }
.guide-card p { font-size: 0.85rem; color: var(--text-secondary); line-height: 1.7; margin: 0; }

.help-modal-overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.6);
    z-index: 10000;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}
.help-modal-overlay.show { display: flex; }
.help-modal {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    max-width: 480px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    position: relative;
}
.help-modal h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 4px; }
.help-modal .help-subtitle { color: var(--text-muted); font-size: 0.82rem; margin-bottom: 20px; }
.help-modal .close-help {
    position: absolute;
    top: 12px; right: 16px;
    background: none; border: none;
    color: var(--text-muted); font-size: 1.4rem;
    cursor: pointer;
    transition: color var(--transition);
}
.help-modal .close-help:hover { color: var(--text-primary); }
.help-shortcuts { display: flex; flex-direction: column; gap: 6px; }
.help-shortcut { display: flex; justify-content: space-between; align-items: center; padding: 8px 0; border-bottom: 1px solid var(--border); }
.help-shortcut:last-child { border-bottom: none; }
.help-shortcut .key-label { color: var(--text-secondary); font-size: 0.88rem; }
.help-shortcut kbd {
    background: var(--bg-elevated);
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 0.78rem;
    color: var(--text-primary);
    border: 1px solid var(--border);
    font-family: inherit;
}

.custom-toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--bg-elevated);
    color: var(--text-primary);
    padding: 10px 22px;
    border-radius: 30px;
    font-size: 0.85rem;
    font-weight: 500;
    z-index: 10000;
    pointer-events: none;
    opacity: 0;
    transition: all 0.35s cubic-bezier(0.4,0,0.2,1);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
    white-space: nowrap;
}
.custom-toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.custom-toast.success { border-color: var(--success); background: rgba(52,211,153,0.15); color: var(--success); }
.custom-toast.info { border-color: var(--accent); background: var(--accent-glow); color: var(--accent); }

.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 44px;
    height: 44px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 50%;
    color: var(--text-secondary);
    font-size: 1rem;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    z-index: 999;
}
.back-to-top:hover { background: var(--accent); color: #fff; border-color: var(--accent); transform: translateY(-3px); }
.back-to-top.show { display: flex; }

@media (max-width: 768px) {
    .toolbar-container { gap: 4px; padding: 6px 8px; }
    .toolbar-container .btn { font-size: 0.75rem; padding: 5px 8px; }
    .guide-grid { grid-template-columns: 1fr; }
    .footer-container { grid-template-columns: 1fr 1fr; }
    .editor-preview-row { padding: 8px 12px 12px; }
    .page-heading { padding: 12px 12px 0; font-size: 1rem; }
    .help-modal { padding: 20px; }
}

/* Light theme overrides */
[data-theme="light"] body { color: var(--text-primary); }
[data-theme="light"] .navbar-brand { color: var(--text-primary) !important; }
[data-theme="light"] .dropdown-menu { background: var(--bg-card) !important; border-color: var(--border) !important; }
[data-theme="light"] .dropdown-item { color: var(--text-secondary); }
[data-theme="light"] .dropdown-item:hover { background: var(--bg-secondary); }
[data-theme="light"] .site-footer { border-top-color: var(--border); }
[data-theme="light"] .site-footer .footer-col ul li a { color: var(--text-muted); }
[data-theme="light"] .site-footer .footer-col ul li a:hover { color: var(--text-primary); }
[data-theme="light"] .site-footer .footer-bottom { border-top-color: var(--border); }
[data-theme="light"] [style*="background:#1a1d23"] { background: var(--bg-card) !important; }
[data-theme="light"] [style*="background:#15171c"] { background: var(--bg-secondary) !important; }
[data-theme="light"] [style*="color:#e0e0e0"] { color: var(--text-primary) !important; }
[data-theme="light"] [style*="color:#c8ccd4"] { color: var(--text-secondary) !important; }
[data-theme="light"] [style*="color:#9ca3af"] { color: var(--text-muted) !important; }
[data-theme="light"] [style*="color:#6b7280"] { color: var(--text-muted) !important; }
[data-theme="light"] [style*="border:1px solid #333"] { border-color: var(--border) !important; }
[data-theme="light"] .preview-frame { border-color: var(--border) !important; }
[data-theme="light"] .CodeMirror { border-color: var(--border) !important; }
[data-theme="light"] .btn-outline-secondary { color: var(--text-secondary) !important; border-color: var(--border) !important; }
[data-theme="light"] .btn-outline-secondary:hover { background: var(--bg-secondary) !important; }
[data-theme="light"] .form-control { background: var(--bg-input) !important; }
[data-theme="light"] .form-control.bg-dark { background: var(--bg-input) !important; color: var(--text-primary) !important; border-color: var(--border) !important; }
[data-theme="light"] h1, [data-theme="light"] h2, [data-theme="light"] h3, [data-theme="light"] h4 { color: var(--text-primary) !important; }

.friend-links { background: var(--bg-primary); border-top: 1px solid var(--border); padding: 20px 16px; text-align: center; }
.friend-links-container { max-width: 900px; margin: 0 auto; }
.friend-links-title { color: var(--text-muted); font-size: 0.78rem; margin-right: 12px; }
.friend-links a { color: var(--text-secondary); font-size: 0.78rem; margin: 0 6px; text-decoration: none; transition: color var(--transition); }
.friend-links a:hover { color: var(--accent); }
.friend-divider { color: var(--border); font-size: 0.7rem; }

/* Print */
@media print {
    .navbar, .toolbar-container, .status-bar, .faq-section, .guide-section, .site-footer, .custom-toast, .back-to-top { display: none !important; }
}