/* ===== CSS Variables ===== */
:root {
    --bg: #f5f7fa;
    --bg-card: #ffffff;
    --bg-sidebar: #1a1d23;
    --bg-input: #f0f2f5;
    --text: #1a1d23;
    --text-secondary: #6b7280;
    --text-sidebar: #a0a4ab;
    --text-sidebar-active: #ffffff;
    --border: #e5e7eb;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #eef2ff;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.08);
    --radius: 12px;
    --radius-sm: 8px;
    --sidebar-width: 260px;
    --topbar-height: 60px;
    --transition: 0.2s ease;
}

[data-theme="dark"] {
    --bg: #0f1117;
    --bg-card: #1a1d23;
    --bg-input: #252830;
    --text: #e5e7eb;
    --text-secondary: #9ca3af;
    --border: #2d3139;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.4);
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

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

/* ===== Sidebar ===== */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-sidebar);
    color: var(--text-sidebar);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 100;
    transition: transform 0.3s ease;
    overflow-y: auto;
}

.sidebar-header {
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 24px;
}

.logo-text {
    font-size: 18px;
    font-weight: 700;
    color: #fff;
    letter-spacing: -0.5px;
}

.sidebar-close {
    display: none;
    background: none;
    border: none;
    color: var(--text-sidebar);
    font-size: 20px;
    cursor: pointer;
}

.sidebar-nav {
    flex: 1;
    padding: 12px 0;
}

.nav-section {
    padding: 0 12px;
    margin-bottom: 8px;
}

.nav-section-title {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: rgba(255,255,255,0.35);
    padding: 12px 12px 6px;
}

.nav-item {
    display: block;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    color: var(--text-sidebar);
    text-decoration: none;
    font-size: 13.5px;
    font-weight: 500;
    transition: all var(--transition);
    cursor: pointer;
}

.nav-item:hover {
    background: rgba(255,255,255,0.06);
    color: #fff;
}

.nav-item.active {
    background: var(--primary);
    color: #fff;
}

.sidebar-footer {
    padding: 16px 20px;
    border-top: 1px solid rgba(255,255,255,0.08);
}

.theme-toggle {
    width: 100%;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    border: 1px solid rgba(255,255,255,0.12);
    background: transparent;
    color: var(--text-sidebar);
    font-size: 13px;
    cursor: pointer;
    transition: all var(--transition);
}

.theme-toggle:hover {
    background: rgba(255,255,255,0.06);
    color: #fff;
}

/* ===== Main ===== */
.main {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.topbar {
    height: var(--topbar-height);
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 24px;
    gap: 16px;
    position: sticky;
    top: 0;
    z-index: 50;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 22px;
    cursor: pointer;
    color: var(--text);
    padding: 4px;
}

.page-title {
    font-size: 18px;
    font-weight: 600;
    flex: 1;
}

.topbar-link {
    font-size: 13px;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    transition: all var(--transition);
}

.topbar-link:hover {
    background: var(--bg-input);
    color: var(--text);
}

.content {
    flex: 1;
    padding: 24px;
    max-width: 960px;
    width: 100%;
    margin: 0 auto;
}

/* ===== Tool Panel ===== */
.tool-panel {
    display: none;
}

.tool-panel.active {
    display: block;
    animation: fadeIn 0.25s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.tool-description {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 20px;
    line-height: 1.6;
}

.tool-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}

.tool-card-title {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

/* ===== Form Elements ===== */
textarea, input[type="text"], input[type="number"], select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-input);
    color: var(--text);
    font-size: 14px;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    line-height: 1.6;
    transition: border-color var(--transition);
    resize: vertical;
}

textarea:focus, input[type="text"]:focus, input[type="number"]:focus, select:focus {
    outline: none;
    border-color: var(--primary);
}

textarea {
    min-height: 200px;
}

.output-area {
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 13px;
    line-height: 1.7;
    white-space: pre-wrap;
    word-break: break-all;
    min-height: 100px;
    max-height: 500px;
    overflow-y: auto;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    border-radius: var(--radius-sm);
    border: none;
    font-size: 13.5px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    font-family: inherit;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(99,102,241,0.3);
}

.btn-secondary {
    background: var(--bg-input);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--border);
}

.btn-danger {
    background: var(--danger);
    color: #fff;
}

.btn-danger:hover {
    background: #dc2626;
}

.btn-sm {
    padding: 6px 14px;
    font-size: 12.5px;
}

.btn-group {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 12px;
}

/* ===== Stats ===== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 12px;
    margin-bottom: 20px;
}

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

.stat-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1;
}

.stat-label {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 6px;
    font-weight: 500;
}

/* ===== Diff ===== */
.diff-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.diff-line {
    padding: 2px 8px;
    font-family: 'SF Mono', monospace;
    font-size: 13px;
    line-height: 1.6;
}

.diff-add {
    background: rgba(16,185,129,0.12);
    color: var(--success);
}

.diff-remove {
    background: rgba(239,68,68,0.12);
    color: var(--danger);
}

.diff-same {
    color: var(--text-secondary);
}

/* ===== Color Picker ===== */
.color-preview {
    width: 100%;
    height: 80px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    margin-bottom: 16px;
    transition: background 0.15s;
}

.color-input-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 12px;
}

.color-field label {
    display: block;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

/* ===== Options Row ===== */
.options-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    align-items: center;
    margin-bottom: 16px;
}

.option-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
}

.option-item label {
    color: var(--text-secondary);
    font-weight: 500;
    white-space: nowrap;
}

.option-item select, .option-item input[type="number"] {
    width: auto;
    min-width: 80px;
    padding: 6px 10px;
    font-size: 13px;
}

.option-item input[type="checkbox"] {
    accent-color: var(--primary);
    width: 16px;
    height: 16px;
}

/* ===== Regex ===== */
.regex-match {
    background: rgba(99,102,241,0.15);
    color: var(--primary);
    padding: 1px 3px;
    border-radius: 3px;
    font-weight: 600;
}

.regex-groups {
    margin-top: 12px;
}

.regex-group-item {
    padding: 8px 12px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    margin-bottom: 6px;
    font-size: 13px;
    font-family: monospace;
}

/* ===== Toast ===== */
.toast {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: var(--bg-sidebar);
    color: #fff;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 999;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .sidebar-close {
        display: block;
    }

    .main {
        margin-left: 0;
    }

    .menu-toggle {
        display: block;
    }

    .content {
        padding: 16px;
    }

    .diff-container {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* ===== Tabs ===== */
.tab-bar {
    display: flex;
    gap: 0;
    border-bottom: 2px solid var(--border);
    margin-bottom: 16px;
}

.tab-btn {
    padding: 10px 20px;
    border: none;
    background: none;
    color: var(--text-secondary);
    font-size: 13.5px;
    font-weight: 600;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all var(--transition);
    font-family: inherit;
}

.tab-btn:hover {
    color: var(--text);
}

.tab-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

/* ===== Copyable Output ===== */
.output-wrapper {
    position: relative;
}

.copy-btn {
    position: absolute;
    top: 8px;
    right: 8px;
    padding: 4px 10px;
    font-size: 11px;
    border-radius: 4px;
    background: var(--primary);
    color: #fff;
    border: none;
    cursor: pointer;
    opacity: 0;
    transition: opacity var(--transition);
    font-family: inherit;
    font-weight: 600;
}

.output-wrapper:hover .copy-btn {
    opacity: 1;
}

/* ===== Cron ===== */
.cron-fields {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    margin-bottom: 16px;
}

.cron-field {
    text-align: center;
}

.cron-field label {
    display: block;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.cron-field input {
    text-align: center;
    padding: 8px;
    font-size: 14px;
    font-weight: 600;
}

.cron-next-runs {
    margin-top: 12px;
}

.cron-run-item {
    padding: 8px 12px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    margin-bottom: 4px;
    font-size: 13px;
    display: flex;
    justify-content: space-between;
}

/* ===== Hidden ===== */
.hidden { display: none !important; }