:root {
    --bg: #f5f7fb;
    --bg-accent: #eef3fb;
    --panel: rgba(255, 255, 255, 0.9);
    --panel-border: rgba(148, 163, 184, 0.22);
    --text: #111827;
    --muted: #6b7280;
    --blue: #2f6db6;
    --blue-soft: #dbe9ff;
    --amber: #d89b3d;
    --amber-soft: #fff1d8;
    --green: #22a05d;
    --green-soft: #ddf8e8;
    --violet: #8b5cf6;
    --violet-soft: #f0e8ff;
    --shadow: 0 12px 34px rgba(15, 23, 42, 0.08);
    --shadow-hover: 0 18px 38px rgba(15, 23, 42, 0.12);
    --radius: 18px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at top center, rgba(191, 219, 254, 0.42), transparent 34%),
        linear-gradient(180deg, #fbfcfe 0%, var(--bg) 44%, #f3f6fb 100%);
}

button,
input,
textarea {
    font: inherit;
}

button {
    border: 0;
}

.app-shell {
    display: grid;
    grid-template-columns: 210px minmax(0, 1fr);
    min-height: 100vh;
}

.sidebar {
    padding: 28px 20px;
    border-right: 1px solid rgba(148, 163, 184, 0.18);
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(247, 250, 255, 0.88));
    backdrop-filter: blur(16px);
}

.brand-block {
    margin-bottom: 28px;
}

.brand-kicker {
    margin: 0 0 8px;
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--blue);
}

.brand-block h1 {
    margin: 0 0 10px;
    font-size: 1.55rem;
    line-height: 1.05;
}

.brand-block p,
.panel-header span,
.topbar-subtitle,
.selection-card span,
.selection-card p,
.notice,
label span,
.cell-card span,
.metric-label {
    color: var(--muted);
}

.nav-list {
    display: grid;
    gap: 6px;
}

.nav-item {
    padding: 12px 14px;
    border-radius: 12px;
    background: transparent;
    color: #4b5563;
    text-align: left;
    transition: background 160ms ease, color 160ms ease, transform 160ms ease;
}

.nav-item:hover {
    background: rgba(47, 109, 182, 0.08);
    color: var(--blue);
    transform: translateX(2px);
}

.nav-item.active {
    background: linear-gradient(180deg, #eef4ff, #e6efff);
    color: var(--blue);
    box-shadow: inset 0 0 0 1px rgba(47, 109, 182, 0.08);
}

.workspace {
    padding: 34px 40px;
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 18px;
    margin-bottom: 24px;
}

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

.topbar h1 {
    margin: 0 0 8px;
    font-size: clamp(2.1rem, 4vw, 3rem);
    line-height: 1.05;
}

.toolbar-button {
    border-radius: 12px;
    padding: 12px 18px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 160ms ease, box-shadow 160ms ease, opacity 160ms ease;
}

.toolbar-button:hover {
    transform: translateY(-1px);
}

.toolbar-button.primary {
    background: linear-gradient(180deg, #3b82f6, #2563eb);
    color: white;
    box-shadow: 0 10px 24px rgba(37, 99, 235, 0.24);
}

.toolbar-button.subtle {
    background: linear-gradient(180deg, #ffffff, #f7f8fb);
    color: #334155;
    border: 1px solid rgba(148, 163, 184, 0.24);
}

.toolbar-button.danger {
    background: linear-gradient(180deg, #fff5f5, #feecec);
    color: #b91c1c;
    border: 1px solid rgba(220, 38, 38, 0.12);
    box-shadow: 0 8px 18px rgba(220, 38, 38, 0.08);
}

.toolbar-button.primary:disabled {
    opacity: 0.65;
    cursor: progress;
}

.dashboard-stack,
.stack {
    display: grid;
    gap: 22px;
}

.panel,
.metric-card,
.selection-card,
.cell-card,
.notice {
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(250, 251, 255, 0.92));
    border: 1px solid var(--panel-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.panel {
    padding: 18px;
}

.panel-header,
.chart-meta {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 18px;
}

.panel-header h2,
.chart-meta h2 {
    margin: 0;
    font-size: 1.05rem;
}

.metric-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.metric-card {
    padding: 18px 18px 16px;
    transition: transform 160ms ease, box-shadow 160ms ease;
}

.metric-card:hover,
.selection-card:hover,
.cell-card:hover,
.panel:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.metric-card.blue { background-image: linear-gradient(180deg, #ffffff, #f7faff); }
.metric-card.amber { background-image: linear-gradient(180deg, #ffffff, #fffaf1); }
.metric-card.green { background-image: linear-gradient(180deg, #ffffff, #f5fff9); }
.metric-card.violet { background-image: linear-gradient(180deg, #ffffff, #faf7ff); }

.metric-label {
    margin-bottom: 10px;
    font-size: 0.95rem;
    font-weight: 500;
}

.metric-value {
    font-size: 1.1rem;
    font-weight: 700;
    line-height: 1.2;
}

.chart-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
}

.chart-meta strong {
    display: block;
    margin-top: 8px;
    font-size: 1rem;
}

.chart-panel canvas {
    width: 100% !important;
    height: 170px !important;
}

.cell-grid,
.selection-grid {
    display: grid;
    gap: 16px;
}

.cell-grid {
    grid-template-columns: repeat(auto-fill, minmax(156px, 1fr));
}

.selection-grid {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
}

.selection-card,
.cell-card {
    padding: 14px;
    text-align: left;
    transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease;
}

.selection-card.active {
    border-color: rgba(47, 109, 182, 0.4);
    box-shadow: 0 0 0 3px rgba(47, 109, 182, 0.08), var(--shadow);
}

.selection-card strong,
.cell-card strong {
    display: block;
    margin-bottom: 8px;
    font-size: 1rem;
}

.selection-card p {
    margin: 4px 0 0;
}

.delete-link {
    display: inline-block;
    margin-top: 10px;
    color: #b91c1c;
    font-size: 0.86rem;
    font-weight: 600;
}

.cell-voltage {
    margin-bottom: 6px;
    font-size: 0.95rem;
    font-weight: 700;
}

.cell-card.is-faulty {
    border-color: rgba(220, 38, 38, 0.24);
    background: linear-gradient(180deg, #ffffff, #fff6f6);
}

.form-panel {
    max-width: 820px;
}

.field-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
}

label {
    display: grid;
    gap: 8px;
}

input,
textarea {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid rgba(148, 163, 184, 0.28);
    border-radius: 12px;
    background: #ffffff;
    color: var(--text);
    transition: border-color 160ms ease, box-shadow 160ms ease;
}

input:focus,
textarea:focus {
    outline: none;
    border-color: rgba(59, 130, 246, 0.45);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.08);
}

.notice {
    margin-bottom: 18px;
    padding: 14px 16px;
}

.notice.inline {
    margin-bottom: 14px;
}

.notice.success {
    background: linear-gradient(180deg, #ffffff, #f3fff8);
}

.notice.error {
    background: linear-gradient(180deg, #ffffff, #fff5f5);
}

.confirm-backdrop {
    position: fixed;
    inset: 0;
    display: grid;
    place-items: center;
    padding: 20px;
    background: rgba(15, 23, 42, 0.26);
    backdrop-filter: blur(3px);
    z-index: 50;
}

.confirm-dialog {
    width: min(420px, 100%);
    padding: 22px;
    border-radius: 18px;
    border: 1px solid rgba(148, 163, 184, 0.2);
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(248, 250, 252, 0.96));
    box-shadow: 0 22px 48px rgba(15, 23, 42, 0.18);
}

.confirm-dialog h3 {
    margin: 0 0 10px;
    font-size: 1.05rem;
}

.confirm-dialog p {
    margin: 0;
    color: var(--muted);
    line-height: 1.5;
}

.confirm-actions {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 20px;
}

.empty-panel {
    max-width: 560px;
}

.empty-panel h2 {
    margin-top: 0;
}

@media (max-width: 1180px) {
    .metric-grid,
    .chart-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 920px) {
    .app-shell {
        grid-template-columns: 1fr;
    }

    .sidebar {
        border-right: 0;
        border-bottom: 1px solid rgba(148, 163, 184, 0.18);
    }

    .workspace {
        padding: 24px 18px;
    }

    .topbar {
        flex-direction: column;
        align-items: stretch;
    }

    .topbar-actions {
        width: 100%;
        flex-wrap: wrap;
    }
}

@media (max-width: 720px) {
    .metric-grid,
    .chart-grid,
    .field-grid {
        grid-template-columns: 1fr;
    }
}