:root {
    --sidebar-w: 272px;
    --font: 'Plus Jakarta Sans', 'Segoe UI', system-ui, sans-serif;
    --bg: #eef2f7;
    --bg-accent: radial-gradient(ellipse 80% 60% at 50% -10%, rgba(59, 130, 246, 0.12), transparent 60%);
    --surface: #ffffff;
    --surface-2: #f8fafc;
    --surface-3: #f1f5f9;
    --border: #e2e8f0;
    --border-strong: #cbd5e1;
    --text: #0f172a;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-soft: #eff6ff;
    --violet: #8b5cf6;
    --violet-soft: #f5f3ff;
    --emerald: #10b981;
    --emerald-soft: #ecfdf5;
    --sidebar-from: #0b1120;
    --sidebar-to: #131c31;
    --success: #059669;
    --error: #dc2626;
    --error-bg: #fef2f2;
    --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.04);
    --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.06);
    --shadow: 0 8px 30px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 20px 50px rgba(15, 23, 42, 0.12);
    --radius: 14px;
    --radius-sm: 10px;
    --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font);
    background: var(--bg);
    background-image: var(--bg-accent);
    color: var(--text);
    line-height: 1.55;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

code {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.15);
    padding: 2px 7px;
    border-radius: 5px;
    font-size: 0.82em;
    font-family: ui-monospace, monospace;
}

/* ── Layout ─────────────────────────────────────────── */
.layout { display: flex; min-height: 100vh; }

.sidebar {
    width: var(--sidebar-w);
    min-width: var(--sidebar-w);
    background: linear-gradient(180deg, var(--sidebar-from) 0%, var(--sidebar-to) 100%);
    color: #fff;
    display: flex;
    flex-direction: column;
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 200;
    border-right: 1px solid rgba(255, 255, 255, 0.06);
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.15);
    transition: transform var(--transition);
}

.sidebar__brand {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 26px 22px 22px;
}

.sidebar__logo {
    width: 46px;
    height: 46px;
    background: linear-gradient(135deg, #3b82f6, #6366f1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    box-shadow: 0 4px 14px rgba(59, 130, 246, 0.45);
    flex-shrink: 0;
}

.sidebar__brand-text strong {
    display: block;
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: -0.03em;
}

.sidebar__brand-text span {
    font-size: 0.72rem;
    color: #64748b;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.sidebar__nav {
    flex: 1;
    padding: 8px 14px 16px;
    display: flex;
    flex-direction: column;
    gap: 3px;
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 11px 14px;
    border: none;
    background: transparent;
    color: #94a3b8;
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-align: left;
    transition: background var(--transition), color var(--transition), transform 0.15s;
}

.nav-item:hover {
    background: rgba(255, 255, 255, 0.06);
    color: #e2e8f0;
}

.nav-item--active {
    background: linear-gradient(90deg, rgba(59, 130, 246, 0.22), rgba(99, 102, 241, 0.12));
    color: #fff;
    box-shadow: inset 3px 0 0 #3b82f6;
}

.nav-item__icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.04);
    flex-shrink: 0;
}

.nav-item--active .nav-item__icon {
    background: rgba(59, 130, 246, 0.25);
    color: #93c5fd;
}

.sidebar__dataset {
    margin: 0 14px 14px;
    padding: 14px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-sm);
    display: flex;
    gap: 12px;
    align-items: flex-start;
}

.sidebar__dataset-icon {
    width: 36px;
    height: 36px;
    background: rgba(16, 185, 129, 0.15);
    color: #34d399;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.sidebar__dataset-label {
    display: block;
    color: #64748b;
    font-size: 0.68rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: 600;
    margin-bottom: 3px;
}

.sidebar__dataset strong {
    display: block;
    font-size: 0.82rem;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 170px;
    color: #f1f5f9;
}

.sidebar__dataset span:last-child {
    font-size: 0.75rem;
    color: #64748b;
}

.sidebar__footer {
    padding: 16px 22px 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.sidebar__footer-badge {
    font-size: 0.75rem;
    color: #64748b;
}

.sidebar-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 150;
    backdrop-filter: blur(2px);
}

.sidebar-backdrop.visible { display: block; }

.main-wrapper {
    flex: 1;
    margin-left: var(--sidebar-w);
    min-width: 0;
    display: flex;
    flex-direction: column;
}

/* ── Topbar ─────────────────────────────────────────── */
.topbar {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 18px;
    padding: 18px 32px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.topbar__toggle {
    display: none;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 9px;
    cursor: pointer;
    color: var(--text);
    transition: background var(--transition);
}

.topbar__toggle:hover { background: var(--surface-2); }

.topbar__eyebrow {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--primary);
    margin-bottom: 2px;
}

.topbar__title h1 {
    font-size: 1.45rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.topbar__title p {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: 2px;
}

.topbar__actions {
    margin-left: auto;
    display: flex;
    gap: 8px;
}

.content {
    padding: 28px 32px 48px;
    flex: 1;
}

.page.hidden { display: none; }

/* ── Stats ──────────────────────────────────────────── */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 28px;
}

.stat-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px 24px;
    display: flex;
    align-items: center;
    gap: 18px;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition), box-shadow var(--transition);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    border-radius: var(--radius) var(--radius) 0 0;
}

.stat-card--blue::before { background: linear-gradient(90deg, #3b82f6, #60a5fa); }
.stat-card--violet::before { background: linear-gradient(90deg, #8b5cf6, #a78bfa); }
.stat-card--emerald::before { background: linear-gradient(90deg, #10b981, #34d399); }

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.stat-card__icon {
    width: 52px;
    height: 52px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.stat-card--blue .stat-card__icon { background: var(--primary-soft); color: var(--primary-dark); }
.stat-card--violet .stat-card__icon { background: var(--violet-soft); color: var(--violet); }
.stat-card--emerald .stat-card__icon { background: var(--emerald-soft); color: var(--emerald); }

.stat-card__label {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.stat-card__value {
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: -0.04em;
    line-height: 1;
    color: var(--text);
}

/* ── Panels ─────────────────────────────────────────── */
.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.panel__header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
    background: linear-gradient(180deg, var(--surface) 0%, var(--surface-2) 100%);
}

.panel__header h2 {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.panel__header p {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-top: 2px;
    width: 100%;
}

.panel__meta { font-size: 0.82rem; color: var(--text-muted); }
.panel__toolbar { display: flex; gap: 8px; }
.panel__body { padding: 24px; }

/* ── Quick actions ──────────────────────────────────── */
.quick-actions { display: flex; flex-direction: column; gap: 10px; }

.action-card {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 18px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-align: left;
    font-family: inherit;
    transition: all var(--transition);
    width: 100%;
}

.action-card:hover {
    border-color: var(--primary);
    background: var(--primary-soft);
    transform: translateX(4px);
    box-shadow: var(--shadow-sm);
}

.action-card__icon {
    width: 44px;
    height: 44px;
    border-radius: 11px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.action-card__icon--blue { background: var(--primary-soft); color: var(--primary-dark); }
.action-card__icon--violet { background: var(--violet-soft); color: var(--violet); }
.action-card__icon--emerald { background: var(--emerald-soft); color: var(--emerald); }

.action-card strong { display: block; font-size: 0.9rem; font-weight: 600; }
.action-card p { font-size: 0.8rem; color: var(--text-muted); margin-top: 2px; }

.action-card__arrow {
    margin-left: auto;
    color: var(--text-light);
    font-size: 1.1rem;
    transition: transform var(--transition), color var(--transition);
}

.action-card:hover .action-card__arrow {
    transform: translateX(4px);
    color: var(--primary);
}

/* ── Recent list ────────────────────────────────────── */
.recent-list { display: flex; flex-direction: column; gap: 8px; }

.recent-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 16px;
    background: var(--surface-2);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all var(--transition);
}

.recent-item:hover {
    border-color: var(--primary);
    background: var(--primary-soft);
}

.recent-item strong { font-size: 0.875rem; font-weight: 600; }
.recent-item span { font-size: 0.75rem; color: var(--text-muted); display: block; margin-top: 2px; }

/* ── Dropzone ───────────────────────────────────────── */
.dropzone {
    border: 2px dashed var(--border-strong);
    border-radius: var(--radius);
    padding: 60px 32px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition);
    background: linear-gradient(180deg, var(--surface-2) 0%, var(--surface) 100%);
}

.dropzone:hover, .dropzone:focus, .dropzone.dragover {
    border-color: var(--primary);
    background: var(--primary-soft);
    outline: none;
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
}

.dropzone__icon { color: var(--primary); margin-bottom: 18px; }
.dropzone__title { font-size: 1.05rem; font-weight: 600; margin-bottom: 8px; }
.text-link { color: var(--primary-dark); text-decoration: underline; text-underline-offset: 2px; }
.dropzone__hint { font-size: 0.85rem; color: var(--text-muted); }

.upload-progress {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 14px;
    padding: 56px;
    color: var(--text-muted);
    font-weight: 500;
}

.spinner {
    width: 24px;
    height: 24px;
    border: 2.5px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

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

/* ── Tables ─────────────────────────────────────────── */
.table-wrap {
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-xs);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

.data-table th, .data-table td {
    padding: 12px 18px;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.data-table th {
    background: var(--surface-3);
    font-weight: 600;
    font-size: 0.72rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.data-table tbody tr { transition: background 0.15s; }
.data-table tbody tr:hover { background: var(--primary-soft); }
.data-table tbody tr:last-child td { border-bottom: none; }

.col-actions { width: 200px; text-align: right !important; }
.row-active { background: var(--primary-soft) !important; }

.badge {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 0.72rem;
    font-weight: 600;
    background: var(--primary-soft);
    color: var(--primary-dark);
}

.badge--active { background: #d1fae5; color: var(--success); }

/* ── Chart workspace ────────────────────────────────── */
.chart-workspace {
    display: grid;
    grid-template-columns: 360px 1fr;
    gap: 24px;
    align-items: start;
}

.chart-form { display: flex; flex-direction: column; gap: 14px; }

.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-group label { font-size: 0.78rem; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.04em; }
.form-group .hint { font-weight: 400; text-transform: none; letter-spacing: 0; }
.form-group--checkbox { justify-content: flex-end; padding-top: 20px; }
.form-group--checkbox label {
    display: flex; align-items: center; gap: 8px;
    color: var(--text); cursor: pointer; font-size: 0.875rem;
    text-transform: none; letter-spacing: 0; font-weight: 500;
}

.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

input[type="text"], input[type="number"], select {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 11px 14px;
    color: var(--text);
    font-size: 0.875rem;
    font-family: inherit;
    transition: border-color var(--transition), box-shadow var(--transition);
}

input:focus, select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.checkbox-grid {
    display: flex;
    flex-direction: column;
    gap: 8px;
    max-height: 150px;
    overflow-y: auto;
    padding: 12px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

.checkbox-grid label {
    display: flex; align-items: center; gap: 8px;
    font-size: 0.85rem; cursor: pointer; font-weight: 500;
    text-transform: none; letter-spacing: 0;
}

.form-actions { display: flex; flex-direction: column; gap: 8px; margin-top: 6px; }

.chart-container {
    position: relative;
    height: 480px;
    background: linear-gradient(180deg, var(--surface-2) 0%, var(--surface) 100%);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 24px;
}

.chart-container.has-chart + .chart-empty,
.chart-container.has-chart ~ .chart-empty { display: none; }

.chart-empty {
    text-align: center;
    padding: 60px 24px;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* ── Saved charts ───────────────────────────────────── */
.saved-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
    gap: 16px;
}

.saved-card {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    background: var(--surface);
    display: flex;
    flex-direction: column;
    gap: 10px;
    transition: box-shadow var(--transition), transform var(--transition);
}

.saved-card:hover {
    box-shadow: var(--shadow);
    transform: translateY(-2px);
}

.saved-card__type {
    font-size: 0.68rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--primary-dark);
    font-weight: 700;
}

.saved-card h3 { font-size: 0.95rem; font-weight: 700; letter-spacing: -0.02em; }
.saved-card p { font-size: 0.8rem; color: var(--text-muted); line-height: 1.5; }
.saved-card__actions { display: flex; gap: 8px; margin-top: auto; padding-top: 8px; }

/* ── Buttons ────────────────────────────────────────── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 7px;
    padding: 11px 18px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
    font-family: inherit;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    letter-spacing: -0.01em;
}

.btn:disabled { opacity: 0.4; cursor: not-allowed; }

.btn--primary {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: #fff;
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.35);
}

.btn--primary:hover:not(:disabled) {
    background: linear-gradient(135deg, #2563eb, #1d4ed8);
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.45);
    transform: translateY(-1px);
}

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

.btn--secondary:hover:not(:disabled) {
    background: var(--surface-2);
    border-color: var(--border-strong);
}

.btn--danger {
    background: var(--error-bg);
    color: var(--error);
    border: 1px solid #fecaca;
}

.btn--danger:hover:not(:disabled) { background: #fee2e2; }

.btn--sm { padding: 8px 13px; font-size: 0.8rem; }
.btn-group { display: flex; gap: 6px; justify-content: flex-end; }

/* ── Alerts & empty ─────────────────────────────────── */
.alert {
    padding: 13px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    margin-bottom: 16px;
    font-weight: 500;
}

.alert--error {
    background: var(--error-bg);
    border: 1px solid #fecaca;
    color: var(--error);
}

.empty-state {
    text-align: center;
    padding: 48px 24px;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.col-type {
    font-size: 0.65rem;
    opacity: 0.55;
    font-weight: 600;
    text-transform: uppercase;
}

/* ── Toast ──────────────────────────────────────────── */
.toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 300;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.toast {
    background: var(--sidebar-from);
    color: #fff;
    padding: 14px 20px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.toast--error { background: var(--error); border-color: transparent; }

@keyframes slideIn {
    from { transform: translateY(16px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.hidden { display: none !important; }

/* ── Responsive ─────────────────────────────────────── */
@media (max-width: 1100px) {
    .chart-workspace { grid-template-columns: 1fr; }
    .grid-2 { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
    .stats-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    .sidebar { transform: translateX(-100%); }
    .sidebar.open { transform: translateX(0); }
    .main-wrapper { margin-left: 0; }
    .topbar__toggle { display: flex; }
    .content { padding: 16px; }
    .topbar { padding: 14px 16px; }
    .form-row { grid-template-columns: 1fr; }
}