* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
    --bg: #f8f9fa;
    --surface: #ffffff;
    --border: #e9ecef;
    --text: #1a1a2e;
    --text-secondary: #6c757d;
    --primary: #00b4d9;
    --primary-light: #e3f7fc;
    --primary-hover: #0099bb;
    --success: #2f9e44;
    --danger: #e03131;
    --warning: #f08c00;
    --radius: 12px;
    --radius-sm: 8px;
    --sidebar-w: 260px;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

/* === Header === */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 0 24px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
}
.header-logo span { font-size: 24px; }
.header-nav { display: flex; gap: 8px; }
.header-nav a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    transition: all 0.2s;
}
.header-nav a:hover, .header-nav a.active { color: var(--primary); background: var(--primary-light); }

/* === Breadcrumb === */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 20px;
}
.breadcrumb a { color: var(--text-secondary); text-decoration: none; }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb .sep { color: #ced4da; }
.breadcrumb .current { color: var(--text); font-weight: 500; }

/* === Layout === */
.layout { display: flex; min-height: calc(100vh - 60px); }
.sidebar {
    width: var(--sidebar-w);
    background: var(--surface);
    border-right: 1px solid var(--border);
    padding: 16px 12px;
    position: sticky;
    top: 60px;
    height: calc(100vh - 60px);
    overflow-y: auto;
    flex-shrink: 0;
}
.sidebar-section { margin-bottom: 20px; }
.sidebar-title {
    font-size: 12px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 0 12px 8px;
    font-weight: 600;
}
.sidebar-link {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: var(--radius-sm);
    color: var(--text);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.2s;
    margin-bottom: 2px;
}
.sidebar-link:hover { background: var(--bg); }
.sidebar-link.active { background: var(--primary-light); color: var(--primary); font-weight: 600; }
.sidebar-link .icon { font-size: 18px; width: 24px; text-align: center; }

.main { flex: 1; padding: 32px; max-width: 100%; overflow-x: hidden; }

/* === Tool Container === */
.tool-header { margin-bottom: 24px; }
.tool-header h1 { font-size: 26px; font-weight: 700; margin-bottom: 8px; }
.tool-header p { color: var(--text-secondary); font-size: 14px; }

/* === Ad === */
.ad-slot {
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    border: 2px dashed #ced4da;
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
    color: #adb5bd;
    font-size: 13px;
    margin: 16px 0;
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* === Cards === */
.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 16px;
}
.card-title {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 8px;
}

/* === Forms === */
.form-row { display: flex; gap: 12px; margin-bottom: 16px; flex-wrap: wrap; }
.form-group { flex: 1; min-width: 200px; }
.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text-secondary);
}
select, input[type="text"], input[type="number"], textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-family: inherit;
    background: var(--surface);
    color: var(--text);
    transition: border-color 0.2s;
}
select:focus, input:focus, textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-light);
}
textarea { resize: vertical; min-height: 160px; font-family: 'SF Mono', 'Fira Code', Consolas, monospace; }

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
    text-decoration: none;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { opacity: 0.9; }
.btn-secondary { background: var(--bg); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { background: #e9ecef; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { opacity: 0.9; }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-group { display: flex; gap: 8px; flex-wrap: wrap; }

/* === Upload === */
.upload-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    background: var(--bg);
}
.upload-zone:hover, .upload-zone.dragover {
    border-color: var(--primary);
    background: var(--primary-light);
}
.upload-zone .upload-icon { font-size: 48px; margin-bottom: 12px; }
.upload-zone p { color: var(--text-secondary); font-size: 14px; }
.upload-zone .formats { margin-top: 8px; font-size: 12px; color: #adb5bd; }

/* === Output === */
.output-box {
    background: #1e1e2e;
    color: #cdd6f4;
    border-radius: var(--radius-sm);
    padding: 16px;
    font-family: 'SF Mono', 'Fira Code', Consolas, monospace;
    font-size: 13px;
    line-height: 1.5;
    overflow-x: auto;
    min-height: 100px;
    white-space: pre-wrap;
    word-break: break-all;
}
.output-box.error { color: #f38ba8; }
.output-box.success { color: #a6e3a1; }

.result-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

/* === Image Preview === */
.image-preview {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
    margin-top: 16px;
}
.image-card {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: var(--surface);
}
.image-card img { width: 100%; height: 140px; object-fit: contain; background: #f1f3f5; }
.image-card .info { padding: 8px 12px; font-size: 12px; }
.image-card .info .name { font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.image-card .info .meta { color: var(--text-secondary); margin-top: 2px; }
.image-card .actions { padding: 0 12px 8px; display: flex; gap: 6px; }

/* === Color === */
.color-preview { width: 100%; height: 80px; border-radius: var(--radius-sm); border: 1px solid var(--border); margin-bottom: 12px; }
input[type="color"] { width: 100%; height: 50px; border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; padding: 4px; }
.color-palette { display: grid; grid-template-columns: repeat(auto-fill, minmax(80px, 1fr)); gap: 8px; }
.palette-item {
    height: 60px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    cursor: pointer;
    position: relative;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    transition: transform 0.15s;
}
.palette-item:hover { transform: scale(1.08); }
.palette-label {
    font-size: 10px;
    color: #fff;
    background: rgba(0,0,0,0.5);
    padding: 2px 6px;
    border-radius: 4px;
    margin-bottom: 4px;
    font-family: 'SF Mono', Consolas, monospace;
}

/* === Toast === */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text);
    color: #fff;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    z-index: 1000;
    transition: transform 0.3s;
    white-space: nowrap;
}
.toast.show { transform: translateX(-50%) translateY(0); }
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }

/* === Stats === */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); gap: 12px; }
.stat-item { background: var(--bg); border-radius: var(--radius-sm); padding: 12px 16px; text-align: center; }
.stat-item .stat-value { font-size: 22px; font-weight: 700; color: var(--primary); }
.stat-item .stat-label { font-size: 12px; color: var(--text-secondary); margin-top: 2px; }

/* === Tabs === */
.tabs { display: flex; gap: 4px; border-bottom: 2px solid var(--border); margin-bottom: 20px; flex-wrap: wrap; }
.tab {
    padding: 8px 16px;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all 0.2s;
    font-family: inherit;
}
.tab:hover { color: var(--text); }
.tab.active { color: var(--primary); border-bottom-color: var(--primary); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* === Converter === */
.converter-row { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; flex-wrap: wrap; }
.converter-row input { flex: 1; min-width: 120px; }
.converter-row select { width: 140px; }
.converter-row .equals { font-size: 20px; color: var(--text-secondary); }

/* === SEO Content === */
.seo-content {
    max-width: 800px;
    margin: 32px 0;
}
.seo-content h2 { font-size: 20px; font-weight: 700; margin: 28px 0 12px; }
.seo-content h3 { font-size: 16px; font-weight: 600; margin: 20px 0 8px; }
.seo-content p { color: #495057; margin-bottom: 12px; }
.seo-content ul, .seo-content ol { margin: 8px 0 16px 20px; }
.seo-content li { margin-bottom: 6px; color: #495057; }
.seo-content table { width: 100%; border-collapse: collapse; margin: 12px 0; }
.seo-content th, .seo-content td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; font-size: 14px; }
.seo-content th { background: var(--bg); font-weight: 600; }
.faq-item { margin-bottom: 16px; }
.faq-item h3 { font-size: 15px; margin-bottom: 6px; color: var(--text); }
.faq-item p { font-size: 14px; color: var(--text-secondary); }

/* === Related Tools === */
.related-tools {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px;
    margin-top: 16px;
}
.related-tool {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text);
    transition: all 0.2s;
    background: var(--surface);
}
.related-tool:hover { border-color: var(--primary); box-shadow: 0 2px 8px rgba(66,99,235,0.1); }
.related-tool .icon { font-size: 24px; }
.related-tool .info .name { font-weight: 600; font-size: 14px; }
.related-tool .info .desc { font-size: 12px; color: var(--text-secondary); }

/* === Home Grid === */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}
.tool-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    text-decoration: none;
    color: var(--text);
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.tool-card:hover {
    border-color: var(--primary);
    box-shadow: 0 4px 16px rgba(66,99,235,0.12);
    transform: translateY(-2px);
}
.tool-card .icon { font-size: 32px; }
.tool-card .name { font-size: 16px; font-weight: 700; }
.tool-card .desc { font-size: 13px; color: var(--text-secondary); }
.tool-card .tags { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 4px; }
.tool-card .tag { font-size: 11px; padding: 2px 8px; background: var(--primary-light); color: var(--primary); border-radius: 4px; }

/* === Footer === */
.footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 32px;
    text-align: center;
    color: var(--text-secondary);
    font-size: 13px;
}
.footer a { color: var(--text-secondary); text-decoration: none; margin: 0 8px; }
.footer a:hover { color: var(--primary); }

/* === Responsive === */
@media (max-width: 768px) {
    .result-grid { grid-template-columns: 1fr; }
    .sidebar { display: none; }
    .main { padding: 16px; }
    .header-nav { display: none; }
    .tool-header h1 { font-size: 20px; }
}

/* === Scrollbar === */
.sidebar::-webkit-scrollbar { width: 6px; }
.sidebar::-webkit-scrollbar-thumb { background: #dee2e6; border-radius: 3px; }
.output-box::-webkit-scrollbar { height: 6px; }
.output-box::-webkit-scrollbar-thumb { background: #45475a; border-radius: 3px; }