:root {
  --ink: #152033;
  --muted: #5b6b80;
  --line: #d5deea;
  --bg: #f3f6fb;
  --paper: #ffffff;
  --brand: #1f4e79;
  --brand-2: #2e75b6;
  --accent: #0f766e;
  --warn: #9a3412;
  --danger: #b42318;
  --soft: #e7eef6;
  --ok: #ecf8f1;
  --shadow: 0 10px 30px rgba(21, 32, 51, 0.08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Segoe UI", "Georgia", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1200px 400px at 10% -10%, #d9e8f6 0%, transparent 50%),
    radial-gradient(900px 300px at 100% 0%, #d8efe8 0%, transparent 46%),
    var(--bg);
}

a { color: var(--brand-2); }
.wrap { width: min(1180px, calc(100% - 32px)); margin: 24px auto 64px; }
.top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 16px 24px;
  background: #12345a;
  color: #fff;
}
.brand { display: flex; align-items: center; gap: 12px; color: inherit; text-decoration: none; }
.brand small { display: block; color: #c5d6ea; font-size: 12px; }
.mark {
  width: 42px; height: 42px; border-radius: 10px;
  display: grid; place-items: center;
  background: #f4c95d; color: #12345a; font-weight: 800;
}
.top nav { display: flex; gap: 16px; }
.top nav a { color: #d7e6f6; text-decoration: none; }
.hero, .panel, .cards article {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
}
.hero { padding: 36px; }
.panel { padding: 24px; margin-bottom: 18px; scroll-margin-top: 56px; }
.eyebrow { text-transform: uppercase; letter-spacing: .08em; color: var(--accent); font-size: 12px; font-weight: 700; margin: 0 0 8px; }
h1, h2, h3 { margin: 0 0 10px; }
.lead { font-size: 18px; line-height: 1.5; color: var(--muted); max-width: 720px; }
.muted { color: var(--muted); }
.hint { color: var(--muted); font-size: 13px; }
.alert {
  background: #fff4ed; color: var(--warn);
  border: 1px solid #f4c7a8; padding: 10px 12px; border-radius: 10px;
}
.join, .inline { display: flex; gap: 12px; align-items: end; flex-wrap: wrap; margin: 20px 0; }
label { display: flex; flex-direction: column; gap: 6px; font-size: 13px; color: var(--muted); }
input, button, .btn {
  font: inherit;
}
input {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  background: #fff;
  color: var(--ink);
}
input:focus { outline: 2px solid #9ec3e6; }
button, .btn {
  background: var(--brand);
  color: #fff;
  border: 0;
  border-radius: 10px;
  padding: 11px 16px;
  text-decoration: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.btn.ghost { background: #e8eef6; color: var(--brand); }
.btn.tiny { padding: 6px 10px; font-size: 12px; }
.btn.danger { background: #fbeaea; color: var(--danger); }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 18px; }
.cards article { padding: 20px; }
.student-head, .row-head {
  display: flex; justify-content: space-between; gap: 16px; align-items: start; margin-bottom: 16px;
}
.actions { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.save-state { font-size: 13px; color: var(--muted); }
.steps {
  display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 16px; position: sticky; top: 8px; z-index: 5;
}
.steps a {
  background: #fff; border: 1px solid var(--line); border-radius: 999px;
  padding: 8px 12px; text-decoration: none; color: var(--ink); box-shadow: var(--shadow);
}
.grid-2, .grid-3 { display: grid; gap: 12px; }
.grid-2 { grid-template-columns: 1fr 1fr; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.search-row { margin: 12px 0 18px; }
.search-row input { width: min(420px, 100%); }
.fuel-group { margin-bottom: 10px; border: 1px solid var(--line); border-radius: 14px; padding: 4px 12px 8px; background: #fbfdff; }
.fuel-group summary { cursor: pointer; display: flex; align-items: center; justify-content: space-between; gap: 12px; list-style: none; padding: 10px 4px; }
.fuel-group summary::-webkit-details-marker { display: none; }
.fuel-group summary::before { content: "▸"; color: var(--brand-2); font-size: 14px; width: 16px; flex: none; }
.fuel-group[open] summary::before { content: "▾"; }
.fuel-group summary h3 { margin: 0; flex: 1; }
.fuel-group summary span { color: var(--muted); font-size: 12px; white-space: nowrap; }
.fuel-list { display: flex; flex-direction: column; gap: 8px; padding: 0 0 8px; }
.fuel-pick {
  border: 1px solid var(--line); border-radius: 12px; background: #fff;
}
.fuel-pick.on { background: #f3fbf7; border-color: #7dbead; }
.fuel-pick-head {
  flex-direction: row; align-items: center; gap: 10px;
  padding: 10px 12px; cursor: pointer; color: var(--ink); font-size: 14px;
}
.fuel-pick-head em { margin-left: auto; color: var(--muted); font-style: normal; font-size: 12px; }
.fuel-body { padding: 12px 12px 14px; border-top: 1px dashed var(--line); }
.fuel-meta p { margin: 0 0 6px; color: var(--muted); font-size: 13px; }
.extra-split { margin-top: 10px; }
.extra-split summary { cursor: pointer; color: var(--brand); font-size: 13px; }
.picked-bar {
  margin: 0 0 14px; padding: 12px 14px; border-radius: 12px;
  background: #ecf8f1; border: 1px solid #b7e0c4;
}
.picked-bar.empty {
  background: #f7fafc; border-style: dashed; border-color: var(--line); color: var(--muted);
}
.picked-label { margin: 0 0 8px; font-size: 13px; color: #166534; font-weight: 600; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  display: inline-flex; align-items: center; gap: 8px;
  border: 1px solid var(--line); border-radius: 999px; padding: 7px 12px;
  background: #fff; color: var(--ink);
}
.chip em { color: var(--muted); font-style: normal; font-size: 12px; }
.chip.on { background: #e6f4ef; border-color: #7dbead; }
.empty-box {
  padding: 24px; border: 1px dashed var(--line); border-radius: 12px; color: var(--muted); text-align: center;
}
.energy-panel.heat { border-left: 5px solid #c9852a; }
.energy-panel.elec { border-left: 5px solid #2e75b6; }
.energy-list { display: flex; flex-direction: column; gap: 8px; }
.energy-row {
  display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 10px; align-items: end;
  padding: 12px; border: 1px solid var(--line); border-radius: 12px; background: #fff;
}
.energy-row.sub { margin-left: 18px; background: #f7fafc; }
.energy-name strong { display: block; color: var(--ink); font-size: 14px; }
.energy-name .code { color: var(--muted); font-size: 12px; }
.unit-hint { margin: 22px 0 0; color: var(--muted); font-size: 13px; }
.note { color: #8a5a12 !important; }
.tags span {
  display: inline-block; background: var(--ok); color: #166534;
  border-radius: 999px; padding: 3px 8px; font-size: 12px; margin-left: 4px;
}
.check { flex-direction: row; align-items: center; }
.table-wrap { overflow: auto; }
table.grid, table.plain { width: 100%; border-collapse: collapse; font-size: 13px; }
table.plain th, table.plain td, table.grid th, table.grid td {
  border: 1px solid var(--line); padding: 8px; vertical-align: middle;
}
table.grid th { background: var(--brand); color: #fff; font-weight: 600; }
table.plain th { background: var(--soft); text-align: left; }
table.grid td.name { text-align: left; }
table.grid input { width: 100%; min-width: 90px; }
td.na, .x { background: #eef3f9; color: #7d8ea3; text-align: center; }
.copy-row { display: flex; gap: 8px; }
.copy-row input { flex: 1; min-width: 220px; }
.share-banner {
  display: flex; justify-content: space-between; gap: 16px; align-items: center; flex-wrap: wrap;
  margin-bottom: 16px; padding: 16px 18px;
  background: #ecf8f1; border: 1px solid #b7e0c4; border-radius: 16px;
}
.share-banner span { display: block; color: var(--muted); font-size: 13px; margin-top: 4px; }
.share-banner .copy-row { min-width: min(420px, 100%); }
.sum-box {
  margin-top: 16px; padding: 16px; border-radius: 12px; background: var(--ok); border: 1px solid #b7e0c4;
}
.actions.end { margin-top: 18px; }
.unit-bar {
  display: flex; gap: 16px; flex-wrap: wrap; margin: 0 0 14px;
}
.unit-bar label { min-width: 220px; }
select {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  background: #fff;
  color: var(--ink);
  font: inherit;
}
.conv-hint {
  margin: 10px 0 0;
  font-size: 13px;
  color: #166534;
  background: var(--ok);
  border-radius: 8px;
  padding: 8px 10px;
}
.conv-hint:empty { display: none; }
.foot { text-align: center; color: var(--muted); padding: 0 16px 28px; font-size: 13px; }

@media (max-width: 860px) {
  .cards, .grid-2, .grid-3, .student-head, .row-head { grid-template-columns: 1fr; display: block; }
  .energy-row { grid-template-columns: 1fr; }
  .energy-row.sub { margin-left: 0; }
  .top { flex-direction: column; align-items: start; }
  .hero { padding: 22px; }
}