/* Denní režim je výchozí; noční platí podle systému, nebo když ho uživatel zapne tlačítkem (data-theme). */
:root {
  color-scheme: light;
  --pozadi: #f2f4f8;
  --pozadi-2: #e7ebf2;
  --plocha: #ffffff;
  --text: #0f172a;
  --tlumene: #64748b;
  --cara: #e2e8f0;
  --mrizka: #edf1f6;
  --akcent: #2563eb;
  --akcent-2: #7c3aed;
  --akcent-text: #ffffff;
  --vybrano: #eef3ff;
  --chyba: #dc2626;
  --ok: #16a34a;
  --stin: 0 1px 2px rgb(15 23 42 / 0.04), 0 4px 16px rgb(15 23 42 / 0.06);
  --stin-maly: 0 1px 2px rgb(15 23 42 / 0.08);
  --zahlavi: rgb(255 255 255 / 0.8);
  --zalozka-vybrana: #ffffff;
  --zaobleni: 14px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --pozadi: #0b0f17;
    --pozadi-2: #161d29;
    --plocha: #121824;
    --text: #e6eaf1;
    --tlumene: #8a96a8;
    --cara: #222b3a;
    --mrizka: #1a2230;
    --akcent: #60a5fa;
    --akcent-2: #a78bfa;
    --akcent-text: #08111f;
    --vybrano: #172640;
    --chyba: #f87171;
    --ok: #4ade80;
    --stin: 0 1px 2px rgb(0 0 0 / 0.3), 0 8px 24px rgb(0 0 0 / 0.25);
    --stin-maly: 0 1px 2px rgb(0 0 0 / 0.4);
    --zahlavi: rgb(18 24 36 / 0.8);
  --zalozka-vybrana: #26334a;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --pozadi: #0b0f17;
  --pozadi-2: #161d29;
  --plocha: #121824;
  --text: #e6eaf1;
  --tlumene: #8a96a8;
  --cara: #222b3a;
  --mrizka: #1a2230;
  --akcent: #60a5fa;
  --akcent-2: #a78bfa;
  --akcent-text: #08111f;
  --vybrano: #172640;
  --chyba: #f87171;
  --ok: #4ade80;
  --stin: 0 1px 2px rgb(0 0 0 / 0.3), 0 8px 24px rgb(0 0 0 / 0.25);
  --stin-maly: 0 1px 2px rgb(0 0 0 / 0.4);
  --zahlavi: rgb(18 24 36 / 0.8);
  --zalozka-vybrana: #26334a;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0;
  background: var(--pozadi);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.2s, color 0.2s;
}

/* ---------- záhlaví ---------- */
header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 24px;
  background: var(--zahlavi);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--cara);
}
.znacka { display: flex; align-items: center; gap: 10px; }
.logo {
  width: 28px;
  height: 28px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--akcent), var(--akcent-2));
  box-shadow: var(--stin-maly);
}
h1 { margin: 0; font-size: 19px; font-weight: 700; letter-spacing: -0.02em; }
h2 { margin: 0 0 4px; font-size: 17px; font-weight: 650; letter-spacing: -0.01em; }
.akce { display: flex; align-items: center; gap: 8px; margin-left: auto; }
.akce form { margin: 0; }

.ikona-tlacitko {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid var(--cara);
  border-radius: 12px;
  background: var(--plocha);
  color: var(--text);
  cursor: pointer;
  transition: background-color 0.15s, border-color 0.15s;
}
.ikona-tlacitko:hover { background: var(--pozadi-2); }
.ikona-tlacitko:focus-visible { outline: 2px solid var(--akcent); outline-offset: 2px; }
.ikona-slunce { display: none; }
.ikona-tlacitko[aria-pressed="true"] .ikona-slunce { display: block; }
.ikona-tlacitko[aria-pressed="true"] .ikona-mesic { display: none; }
.rohove { position: fixed; top: 16px; right: 16px; }

/* ---------- rozložení ---------- */
main {
  display: grid;
  grid-template-columns: 340px minmax(0, 1fr);
  gap: 20px;
  max-width: 1320px;
  margin: 0 auto;
  padding: 20px 24px 32px;
}
.obsah { display: flex; flex-direction: column; gap: 20px; min-width: 0; }
.karta {
  background: var(--plocha);
  border: 1px solid var(--cara);
  border-radius: var(--zaobleni);
  box-shadow: var(--stin);
  padding: 20px;
}
.tlumene { color: var(--tlumene); font-size: 14px; margin: 0; }

/* ---------- záložky (přepínač) ---------- */
.zalozky {
  grid-column: 1 / -1;
  justify-self: start;
  display: flex;
  gap: 4px;
  max-width: 100%;
  padding: 4px;
  overflow-x: auto;
  background: var(--pozadi-2);
  border-radius: 999px;
}
.zalozka {
  flex: none;
  min-height: 40px;
  padding: 8px 20px;
  border: 0;
  border-radius: 999px;
  background: none;
  color: var(--tlumene);
  font: inherit;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s, color 0.15s;
}
.zalozka:hover { color: var(--text); }
.zalozka[aria-selected="true"] { background: var(--zalozka-vybrana); color: var(--akcent); box-shadow: var(--stin-maly); }
.zalozka:focus-visible { outline: 2px solid var(--akcent); outline-offset: 1px; }

/* ---------- menu s hodnotami ---------- */
#menu { display: flex; flex-direction: column; gap: 16px; }
.skupina {
  background: var(--plocha);
  border: 1px solid var(--cara);
  border-radius: var(--zaobleni);
  box-shadow: var(--stin);
  overflow: hidden;
}
.skupina-hlava {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 14px 16px 10px;
  font-weight: 650;
}
.skupina-stav {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 2px 10px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--ok) 12%, transparent);
  color: var(--ok);
  font-size: 12px;
  font-weight: 600;
  text-align: right;
}
.skupina-stav::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: currentColor; flex: none; }
.skupina-stav.spatne { background: color-mix(in srgb, var(--chyba) 12%, transparent); color: var(--chyba); }
.polozka {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  min-height: 48px;
  padding: 10px 16px;
  border: 0;
  border-top: 1px solid var(--cara);
  border-radius: 0;
  background: none;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: background-color 0.15s;
}
.polozka:hover { background: var(--pozadi); }
.polozka[aria-pressed="true"] { background: var(--vybrano); }
.polozka[aria-pressed="true"]::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 3px;
  border-radius: 0 3px 3px 0;
  background: var(--akcent);
}
.polozka:focus-visible { outline: 2px solid var(--akcent); outline-offset: -2px; }
.hodnota { font-size: 17px; font-weight: 650; font-variant-numeric: tabular-nums; white-space: nowrap; letter-spacing: -0.01em; }
.hodnota.stara { color: var(--tlumene); font-weight: 400; }

/* ---------- graf ---------- */
.platno { position: relative; margin-top: 16px; }
canvas { display: block; width: 100%; height: 360px; touch-action: pan-y; }
.popisek {
  position: absolute;
  top: 4px;
  padding: 6px 10px;
  border: 1px solid var(--cara);
  border-radius: 10px;
  background: var(--plocha);
  box-shadow: var(--stin);
  font-size: 13px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  pointer-events: none;
}

/* ---------- chybové kódy kotle ---------- */
.chyba-stav {
  margin: 12px 0 16px;
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  background: var(--pozadi);
  color: var(--tlumene);
}
.chyba-stav[data-stav="ok"] { background: color-mix(in srgb, var(--ok) 12%, transparent); color: var(--ok); }
.chyba-stav[data-stav="chyba"] { background: color-mix(in srgb, var(--chyba) 14%, transparent); color: var(--chyba); }
.kody { width: 100%; border-collapse: collapse; font-size: 14px; margin-bottom: 12px; }
.kody th {
  padding: 8px 10px;
  border-bottom: 1px solid var(--cara);
  color: var(--tlumene);
  font-size: 12px;
  font-weight: 600;
  text-align: left;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.kody td { padding: 10px; border-bottom: 1px solid var(--cara); vertical-align: top; }
.kody tr:last-child td { border-bottom: 0; }
.kody td:first-child { width: 72px; font-weight: 700; font-variant-numeric: tabular-nums; white-space: nowrap; }
.kody tr.obecny td:first-child::after { content: "*"; color: var(--tlumene); font-weight: 400; }
.kody td span { display: block; margin-top: 2px; color: var(--tlumene); font-size: 13px; }
.kody td span:empty { display: none; }
.kody tr.aktualni td { background: color-mix(in srgb, var(--chyba) 12%, transparent); }
.kody tr.aktualni td:first-child { color: var(--chyba); box-shadow: inset 3px 0 0 var(--chyba); }

/* ---------- formuláře ---------- */
.radek { display: flex; flex-wrap: wrap; gap: 12px; align-items: end; margin: 14px 0; }
label { display: block; font-size: 13px; font-weight: 500; color: var(--tlumene); }
input[type=date], input[type=password] {
  display: block;
  width: 100%;
  min-height: 44px;
  margin-top: 6px;
  padding: 8px 12px;
  border: 1px solid var(--cara);
  border-radius: 10px;
  background: var(--pozadi);
  color: var(--text);
  font: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}
input[type=date]:focus, input[type=password]:focus {
  outline: none;
  border-color: var(--akcent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--akcent) 25%, transparent);
}
button[type=submit] {
  min-height: 44px;
  padding: 8px 18px;
  border: 1px solid transparent;
  border-radius: 10px;
  background: var(--akcent);
  color: var(--akcent-text);
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  transition: filter 0.15s, background-color 0.15s;
}
button[type=submit]:hover { filter: brightness(1.08); }
button[type=submit]:focus-visible { outline: 2px solid var(--akcent); outline-offset: 2px; }
button.vedlejsi[type=submit] { background: var(--plocha); border-color: var(--cara); color: var(--text); }
button.vedlejsi[type=submit]:hover { background: var(--pozadi-2); filter: none; }
header button.vedlejsi[type=submit] { min-height: 40px; padding: 4px 14px; border-radius: 12px; }
details { margin: 8px 0; font-size: 14px; }
summary { cursor: pointer; min-height: 28px; font-weight: 500; }
#export-kanaly { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 2px 16px; margin-top: 8px; }
#export-kanaly label { display: flex; align-items: center; gap: 8px; padding: 4px 0; color: var(--text); font-weight: 400; }
input[type=checkbox] { width: 16px; height: 16px; accent-color: var(--akcent); }

/* ---------- přihlášení ---------- */
.prihlaseni {
  display: grid;
  place-items: center;
  min-height: 100vh;
  padding: 16px;
  background:
    radial-gradient(60rem 30rem at 15% -10%, color-mix(in srgb, var(--akcent) 14%, transparent), transparent),
    radial-gradient(50rem 30rem at 110% 110%, color-mix(in srgb, var(--akcent-2) 12%, transparent), transparent),
    var(--pozadi);
}
.prihlaseni .karta { width: 100%; max-width: 360px; padding: 28px; }
.prihlaseni .znacka { margin-bottom: 20px; }
.prihlaseni h1 { font-size: 22px; }
.prihlaseni button[type=submit] { width: 100%; margin-top: 16px; }
.chyba { color: var(--chyba); font-size: 14px; margin: 8px 0 0; }

@media (max-width: 820px) {
  header { padding: 10px 16px; }
  main { grid-template-columns: minmax(0, 1fr); gap: 16px; padding: 16px; }
  .zalozky { justify-self: stretch; }
  .zalozka { flex: 1 0 auto; padding: 8px 14px; }
  .karta { padding: 16px; }
  canvas { height: 280px; }
  #aktualizace { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}