/* ── Semi Design Tokens (Light) ─────────────────────────── */

:root {
    /* Neutral */
    --semi-grey-0: #f9f9f9;
    --semi-grey-1: #f4f4f5;
    --semi-grey-2: #e6e8ea;
    --semi-grey-3: #d1d3d6;
    --semi-grey-4: #b7b9be;
    --semi-grey-5: #9fa2a7;
    --semi-grey-6: #888b91;
    --semi-grey-7: #6b6e75;
    --semi-grey-8: #41464c;
    --semi-grey-9: #1f2329;

    /* Primary (Indigo) */
    --semi-indigo-0: #f4f3f9;
    --semi-indigo-1: #e9e6f3;
    --semi-indigo-2: #d3cdea;
    --semi-indigo-3: #bbb3df;
    --semi-indigo-4: #a296d4;
    --semi-indigo-5: #8879c9;
    --semi-indigo-6: #6e5cbe;
    --semi-indigo-7: #5641b3;
    --semi-indigo-8: #3e2ba8;
    --semi-indigo-9: #28199d;

    /* Danger */
    --semi-red-0: #fef2f2;
    --semi-red-1: #fee2e2;
    --semi-red-2: #fecaca;
    --semi-red-3: #fca5a5;
    --semi-red-4: #f87171;
    --semi-red-5: #ef4444;
    --semi-red-6: #dc2626;
    --semi-red-7: #b91c1c;
    --semi-red-8: #991b1b;
    --semi-red-9: #7f1d1d;

    /* Success */
    --semi-green-0: #f0fdf4;
    --semi-green-1: #dcfce7;
    --semi-green-2: #bbf7d0;
    --semi-green-3: #86efac;
    --semi-green-4: #4ade80;
    --semi-green-5: #22c55e;
    --semi-green-6: #16a34a;
    --semi-green-7: #15803d;
    --semi-green-8: #166534;
    --semi-green-9: #14532d;

    /* ── Semantic Mapping ───────────────────────────────── */
    --bg-body: var(--semi-grey-0);
    --bg-surface: #ffffff;
    --bg-elevated: var(--semi-grey-1);
    --bg-hover: var(--semi-grey-2);
    --border: var(--semi-grey-2);
    --border-hover: var(--semi-grey-3);
    --text-primary: var(--semi-grey-9);
    --text-secondary: var(--semi-grey-7);
    --text-muted: var(--semi-grey-5);
    --accent: var(--semi-indigo-6);
    --accent-hover: var(--semi-indigo-7);
    --accent-active: var(--semi-indigo-8);
    --accent-glow: rgba(110, 92, 190, 0.2);
    --error: var(--semi-red-5);
    --error-bg: var(--semi-red-0);
    --success: var(--semi-green-5);

    /* ── Layout ─────────────────────────────────────────── */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --shadow-sm: 0 1px 2px rgba(31, 35, 41, 0.05);
    --shadow-md: 0 4px 12px rgba(31, 35, 41, 0.08);
    --shadow-glow: 0 0 16px var(--accent-glow);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
    --header-h: 56px;
    --toolbar-h: 48px;
}

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

html, body {
    height: 100%;
    font-family: var(--font-sans);
    background: var(--bg-body);
    color: var(--text-primary);
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
}

/* ── Header ─────────────────────────────────────────────── */
.app-header {
    height: var(--header-h);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
    position: relative;
    z-index: 10;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-logo {
    width: 32px;
    height: 32px;
    flex-shrink: 0;
    filter: drop-shadow(0 0 8px var(--accent-glow));
}

.brand-text h1 {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: -0.3px;
    color: var(--text-primary);
}

.tagline {
    font-size: 11px;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin-left: 4px;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.15s ease;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

/* ── Workspace ──────────────────────────────────────────── */
.workspace {
    display: flex;
    flex: 1;
    height: calc(100vh - var(--header-h));
    overflow: hidden;
}

/* ── Panel ──────────────────────────────────────────────── */
.panel {
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.panel-editor {
    flex: 1;
    min-width: 360px;
    max-width: 60%;
}

.panel-preview {
    flex: 1;
    min-width: 360px;
}

/* ── Toolbar ────────────────────────────────────────────── */
.panel-toolbar {
    height: var(--toolbar-h);
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 0 16px;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}

.toolbar-group {
    display: flex;
    align-items: center;
    gap: 6px;
}

.toolbar-label {
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.toolbar-select {
    appearance: none;
    background: var(--bg-elevated);
    color: var(--text-primary);
    border: 1px solid var(--border);
    padding: 5px 24px 5px 10px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    outline: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23888b91' stroke-width='2.5'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 8px center;
    transition: border-color 0.15s;
}

.toolbar-select:hover, .toolbar-select:focus {
    border-color: var(--border-hover);
}

.toolbar-actions {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: auto;
}

/* ── Buttons ────────────────────────────────────────────── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    outline: none;
    transition: all 0.15s ease;
    white-space: nowrap;
}

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

.btn-ghost:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
    border-color: var(--border-hover);
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 0 0 0 var(--accent-glow);
}

.btn-primary:hover:not(:disabled) {
    background: var(--accent-hover);
    box-shadow: var(--shadow-glow);
    transform: translateY(-1px);
}

.btn-primary:active:not(:disabled) {
    background: var(--accent-active);
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-spinner {
    width: 14px;
    height: 14px;
    border: 2px solid rgba(255,255,255,0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── Editor Surface ─────────────────────────────────────── */
.editor-surface {
    flex: 1;
    overflow: hidden;
    position: relative;
    background: var(--bg-body);
}

#monacoEditor {
    width: 100%;
    height: 100%;
}

/* ── Error Toast ────────────────────────────────────────── */
.error-toast {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    background: var(--error-bg);
    border-top: 1px solid var(--semi-red-1);
    color: var(--error);
    font-size: 12px;
    font-family: var(--font-mono);
    flex-shrink: 0;
    animation: slideUp 0.2s ease;
}

.error-toast.hidden { display: none; }

.error-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(6px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ── Resize Handle ──────────────────────────────────────── */
.resize-handle {
    width: 4px;
    background: var(--border);
    cursor: col-resize;
    flex-shrink: 0;
    transition: background 0.15s;
    position: relative;
}

.resize-handle:hover, .resize-handle.dragging {
    background: var(--accent);
}

.resize-handle::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 2px;
    height: 24px;
    border-radius: 1px;
    background: var(--text-muted);
    opacity: 0.3;
}

/* ── Preview Surface ────────────────────────────────────── */
.preview-surface {
    flex: 1;
    overflow: auto;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: var(--bg-body);
}

.chart-stage {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
}

.chart-stage svg, .chart-stage img {
    max-width: 100%;
    max-height: calc(100vh - var(--header-h) - var(--toolbar-h) - 40px);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    background: var(--bg-surface);
}

/* ── Empty State ────────────────────────────────────────── */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    color: var(--text-muted);
    text-align: center;
    padding: 40px;
}

.empty-icon {
    width: 48px;
    height: 48px;
    opacity: 0.4;
}

.empty-state p {
    font-size: 14px;
    color: var(--text-secondary);
}

.empty-state strong {
    color: var(--text-primary);
    font-weight: 600;
}

.shortcut-hint {
    font-size: 11px;
    font-family: var(--font-mono);
    color: var(--text-muted);
    background: var(--bg-elevated);
    padding: 3px 8px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
}

/* ── Utilities ──────────────────────────────────────────── */
.hidden { display: none !important; }

/* ── Responsive ─────────────────────────────────────────── */
@media (max-width: 768px) {
    .workspace { flex-direction: column; }
    .panel-editor { max-width: none; border-right: none; border-bottom: 1px solid var(--border); }
    .resize-handle { display: none; }
    .panel-toolbar { flex-wrap: wrap; height: auto; padding: 8px 12px; gap: 8px; }
    .toolbar-actions { margin-left: 0; width: 100%; justify-content: flex-end; }
}