:root {
    --accent: #1F3864;
    --ink: #1a1a1a;
    --muted: #6b7280;
    --line: #e5e7eb;
    --bg: #ffffff;
    --bg-soft: #f8f9fb;
    --up: #15803d;
    --down: #b91c1c;
    --flat: #6b7280;
    --stale: #b45309;
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    font-size: 15px;
    line-height: 1.4;
}

.page {
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px 20px 48px;
}

.topbar {
    position: relative;
    text-align: center;
    border-bottom: 2px solid var(--accent);
    padding: 16px 0 18px;
    margin-bottom: 20px;
}

.topbar h1 {
    color: var(--accent);
    margin: 4px 0 0;
    font-size: 26px;
    letter-spacing: -0.01em;
    line-height: 1.2;
}

.topbar .subtle {
    margin: 4px 0 0;
    color: var(--muted);
    font-size: 14px;
}

.brand {
    display: block;
}

.brand-logo {
    display: block;
    margin: 0 auto 4px;
    max-height: 160px;
    width: auto;
}

.topbar-meta {
    position: absolute;
    top: 16px;
    right: 0;
    text-align: right;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 6px;
}

@media (max-width: 700px) {
    .topbar { padding: 12px 0 14px; }
    .brand-logo { max-height: 110px; }
    .topbar h1 { font-size: 19px; }
    .topbar-meta {
        position: static;
        text-align: left;
        align-items: flex-start;
        margin-bottom: 12px;
    }
}

.topbar .subtle { margin: 4px 0 0; color: var(--muted); }

.topbar-meta {
    text-align: right;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 6px;
}

.btn {
    display: inline-block;
    padding: 6px 12px;
    background: var(--accent);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-size: 13px;
}

.btn:hover { opacity: 0.9; }

.banner {
    background: #fff7ed;
    border: 1px solid #fdba74;
    color: #7c2d12;
    padding: 8px 12px;
    border-radius: 6px;
    margin-bottom: 20px;
    font-size: 13px;
}

.banner--info {
    background: #eff6ff;
    border-color: #bfdbfe;
    color: #1e3a8a;
    margin: 28px 0 0;
}

/* Tab navigation -------------------------------------------------------------
   Pure-CSS tabs using :target. Tab panes hide by default; the one whose id
   matches the URL fragment shows. When no fragment is set (initial page load),
   the :has() rule in the body selector falls back to the first tab.
   Sticky on scroll so the tab bar stays reachable on long pages. */
.tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 0;
    border-bottom: 2px solid var(--line);
    margin: 20px 0 18px;
    position: sticky;
    top: 0;
    background: var(--bg);
    z-index: 10;
    /* Faint shadow when scrolled so the bar visually separates from the content. */
    box-shadow: 0 1px 0 var(--line);
}
.tab {
    padding: 10px 18px;
    text-decoration: none;
    color: var(--muted);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    font-weight: 600;
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    transition: color 0.12s, border-color 0.12s;
}
.tab:hover {
    color: var(--accent);
}
.tab.active {
    color: var(--accent);
    border-bottom-color: var(--accent);
}
.tab-pane {
    display: none;
}
.tab-pane:target {
    display: block;
}
/* Default: show the first tab (Gas) when no fragment is set. */
body:not(:has(.tab-pane:target)) #tab-gas {
    display: block;
}

@media (max-width: 700px) {
    .tab { padding: 8px 12px; font-size: 12px; }
}

section {
    margin: 28px 0;
}

h2 {
    color: var(--accent);
    font-size: 17px;
    margin: 0 0 10px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    font-weight: 600;
}

h3.subhead {
    color: var(--ink);
    font-size: 13px;
    font-weight: 600;
    margin: 18px 0 8px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

h3.subhead:first-of-type {
    margin-top: 4px;
}

h4.subsubhead {
    color: var(--muted);
    font-size: 12px;
    font-weight: 600;
    margin: 14px 0 6px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

/* Collapsible forward-curve sections */
details.curve {
    margin: 4px 0;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: var(--bg-soft);
}
details.curve[open] {
    background: white;
    box-shadow: 0 0 0 1px var(--line);
}
details.curve summary {
    padding: 8px 12px;
    cursor: pointer;
    font-size: 13px;
    list-style: none;
    user-select: none;
}
details.curve summary::-webkit-details-marker { display: none; }
details.curve summary::before {
    content: "▸";
    display: inline-block;
    width: 14px;
    color: var(--muted);
    transition: transform 0.15s;
}
details.curve[open] summary::before {
    transform: rotate(90deg);
}
.curve-title {
    font-weight: 600;
    color: var(--accent);
}
.curve-meta {
    color: var(--muted);
    font-size: 12px;
    margin-left: 6px;
}
table.curve-table {
    margin: 0 8px 8px;
    width: calc(100% - 16px);
}

.footnote {
    font-size: 12px;
    color: var(--muted);
    font-style: italic;
    margin: 8px 0 0;
}

table.data {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-soft);
    font-size: 14px;
}

table.data th, table.data td {
    padding: 8px 10px;
    text-align: left;
    border-bottom: 1px solid var(--line);
}

table.data th {
    background: white;
    font-weight: 600;
    color: var(--muted);
    text-transform: uppercase;
    font-size: 11px;
    letter-spacing: 0.05em;
}

table.data tr:last-child td { border-bottom: none; }

table.data .num { text-align: right; font-variant-numeric: tabular-nums; }
table.data .muted, .muted { color: var(--muted); }

/* Sort indicator on column headers (added by JS on click). */
table.data th { user-select: none; position: relative; }
table.data th:hover { color: var(--accent); }
table.data th.sort-asc::after,
table.data th.sort-desc::after {
    content: " ▲";
    color: var(--accent);
    font-size: 9px;
    margin-left: 4px;
    vertical-align: middle;
}
table.data th.sort-desc::after { content: " ▼"; }

/* Mobile-friendly: any .data table inside a section gets horizontal scroll
   when it overflows on narrow screens. Wrapping the table in a div would be
   tidier but this works without template changes. */
section { overflow-x: auto; -webkit-overflow-scrolling: touch; }

tr.stale td { color: var(--stale); }
tr.stale td::after { }

/* Anomaly severity row backgrounds — quiet enough not to overwhelm but
   the eye lands on them when scanning. */
tr.severity-critical td { background: #fef2f2; }
tr.severity-warning td  { background: #fffbeb; }
tr.severity-normal td   { /* default */ }
tr.severity-critical:hover td { background: #fee2e2; }
tr.severity-warning:hover td  { background: #fef3c7; }

/* "Today's notable" box that sits between banner and tabs. */
.notable-box {
    margin: 14px 0 6px;
    padding: 14px 18px;
    background: #fefce8;
    border: 1px solid #fde68a;
    border-radius: 6px;
}
.notable-box h3 {
    margin: 0 0 8px;
    color: #92400e;
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: 700;
}
.notable-box ul {
    margin: 0;
    padding: 0;
    list-style: none;
}
.notable-item {
    padding: 4px 0 4px 12px;
    border-left: 3px solid transparent;
    font-size: 13px;
    margin: 2px 0;
}
.notable-item a {
    color: var(--ink);
    text-decoration: none;
}
.notable-item a:hover { text-decoration: underline; }
.notable-critical { border-left-color: #b91c1c; }
.notable-warning  { border-left-color: #ca8a04; }
.notable-critical a { color: #991b1b; font-weight: 600; }
.notable-warning a  { color: #854d0e; }

.delta { font-variant-numeric: tabular-nums; }
.delta-up   { color: var(--up); }
.delta-down { color: var(--down); }
.delta-flat { color: var(--flat); }

.grid-cards {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
}

.card {
    background: var(--bg-soft);
    border: 1px solid var(--line);
    border-radius: 6px;
    padding: 12px;
}

.card.stale { color: var(--stale); border-color: #fdba74; }
.card-label { font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.04em; }
.card-value { font-size: 22px; font-weight: 600; margin: 4px 0; font-variant-numeric: tabular-nums; }
.card-unit { font-size: 12px; font-weight: 500; color: var(--muted); }
.card-sub { font-size: 12px; color: var(--muted); }
.card-delta { font-size: 13px; font-weight: 500; margin-top: 4px; font-variant-numeric: tabular-nums; }
.sparkline-placeholder { font-size: 11px; color: var(--muted); margin-top: 6px; font-style: italic; }
.sparkline { display: inline-block; vertical-align: middle; }
.sparkline-empty { font-size: 11px; color: var(--muted); font-style: italic; }
.card-spark { margin-top: 6px; height: 20px; }

.grid-cards--two {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.stacked-bar {
    display: flex;
    width: 100%;
    height: 18px;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 12px;
    background: var(--line);
}

.stacked-bar-seg { height: 100%; }
.fuel-1  { background: #1f2937; }   /* Black coal */
.fuel-2  { background: #78350f; }   /* Brown coal */
.fuel-3  { background: #b45309; }   /* Gas */
.fuel-4  { background: #0e7490; }   /* Hydro */
.fuel-5  { background: #15803d; }   /* Wind */
.fuel-6  { background: #ca8a04; }   /* Utility solar */
.fuel-7  { background: #fde047; }   /* Rooftop solar */
.fuel-8  { background: #7c3aed; }   /* Battery */
.fuel-9  { background: #6b7280; }   /* Diesel */
.fuel-10 { background: #94a3b8; }   /* Biomass / other */

footer {
    margin-top: 36px;
    padding-top: 16px;
    border-top: 1px solid var(--line);
    font-size: 12px;
}

@media (max-width: 700px) {
    .page { padding: 12px 12px 32px; }
    table.data { font-size: 13px; min-width: 100%; }
    table.data th, table.data td { padding: 6px 8px; }
    .grid-cards { grid-template-columns: 1fr 1fr; }
    .grid-cards--two { grid-template-columns: 1fr; }
    /* Bigger tab touch targets, scroll horizontally if too many */
    .tabs { overflow-x: auto; flex-wrap: nowrap; -webkit-overflow-scrolling: touch; }
    .tab { padding: 12px 14px; font-size: 12px; flex-shrink: 0; }
    /* Stop the section overflow-x clipping the sticky tabs */
    section { overflow-x: visible; }
    /* Each table in its own scroll container on small screens */
    section table.data { display: block; overflow-x: auto; white-space: nowrap; }
    section table.data thead, section table.data tbody { white-space: normal; }
}