/* ===== Åttans matte – "Planetariet" =====
   Mörk midnattsrymd där matematiken är det som lyser.
   Kall rymd (blåtonade ytor) + varmt ljus (bärnstensgul text/accent). */

:root {
  --bg: oklch(0.21 0.03 265);
  --bg-deep: oklch(0.17 0.028 265);
  --panel: oklch(0.25 0.034 265);
  --panel-2: oklch(0.28 0.036 265);
  --line: oklch(0.35 0.03 265);
  --line-soft: oklch(0.30 0.03 265);

  --ink: oklch(0.93 0.012 85);
  --ink-soft: oklch(0.74 0.02 85);
  --ink-faint: oklch(0.58 0.025 265);

  --amber: oklch(0.82 0.14 80);
  --amber-deep: oklch(0.70 0.14 70);
  --coral: oklch(0.70 0.16 32);
  --green: oklch(0.76 0.12 155);
  --sky: oklch(0.76 0.09 230);

  --amber-tint: oklch(0.27 0.04 80);
  --green-tint: oklch(0.27 0.045 155);
  --coral-tint: oklch(0.26 0.05 32);

  --radius: 8px;
  --font-display: "Familjen Grotesk", system-ui, sans-serif;
  --font-body: "Atkinson Hyperlegible", system-ui, sans-serif;

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.75rem;
  --space-xl: 3rem;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
}

::selection { background: var(--amber); color: var(--bg-deep); }

.icon { vertical-align: -0.18em; flex-shrink: 0; }

/* ---- Topbar ---- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.7rem 1.25rem;
  background: color-mix(in oklch, var(--bg-deep) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line-soft);
}
.brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--ink);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.55rem;
  white-space: nowrap;
  letter-spacing: 0.01em;
}
.brand-eight {
  display: inline-grid;
  place-items: center;
  width: 1.9rem;
  height: 1.9rem;
  border-radius: 50%;
  background: var(--amber);
  color: var(--bg-deep);
  font-size: 1.05rem;
  font-weight: 700;
  transform: rotate(-8deg);
}
.topnav {
  display: flex;
  gap: 0.15rem;
  overflow-x: auto;
  scrollbar-width: none;
}
.topnav::-webkit-scrollbar { display: none; }
.topnav a {
  font-family: var(--font-display);
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--ink-soft);
  text-decoration: none;
  padding: 0.3rem 0.65rem;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
}
.topnav a:hover { color: var(--ink); }
.topnav a.active { color: var(--amber); border-bottom-color: var(--amber); }

/* ---- Layout ---- */
.app { max-width: 880px; margin: 0 auto; padding: var(--space-lg) 1.25rem 4rem; }
.footer {
  max-width: 880px;
  margin: 0 auto;
  padding: var(--space-lg) 1.25rem var(--space-xl);
  color: var(--ink-faint);
  font-size: 0.85rem;
  border-top: 1px solid var(--line-soft);
}

/* ---- Hem / hero ---- */
.hero {
  padding: var(--space-xl) 0 var(--space-lg);
  position: relative;
}
/* stillsam stjärnhimmel – bara på hero */
.hero::before {
  content: "";
  position: absolute;
  inset: -2rem -3rem 0;
  pointer-events: none;
  background-image:
    radial-gradient(1.5px 1.5px at 12% 20%, oklch(0.9 0.02 85 / 0.7) 50%, transparent 51%),
    radial-gradient(1px 1px at 31% 68%, oklch(0.9 0.02 85 / 0.5) 50%, transparent 51%),
    radial-gradient(2px 2px at 48% 12%, oklch(0.85 0.1 80 / 0.6) 50%, transparent 51%),
    radial-gradient(1px 1px at 64% 45%, oklch(0.9 0.02 85 / 0.45) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 79% 24%, oklch(0.9 0.02 85 / 0.6) 50%, transparent 51%),
    radial-gradient(1px 1px at 91% 60%, oklch(0.85 0.1 80 / 0.5) 50%, transparent 51%),
    radial-gradient(1px 1px at 22% 88%, oklch(0.9 0.02 85 / 0.4) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 85% 86%, oklch(0.9 0.02 85 / 0.5) 50%, transparent 51%);
}
.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 7vw, 3.8rem);
  font-weight: 700;
  line-height: 1.06;
  letter-spacing: -0.015em;
  margin: 0 0 1rem;
  position: relative;
}
.hero h1 .hl { color: var(--amber); }
.hero p {
  font-size: 1.12rem;
  color: var(--ink-soft);
  max-width: 36rem;
  margin: 0;
  position: relative;
}

.grade-label {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.92rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  margin: var(--space-xl) 0 var(--space-md);
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.grade-label .icon { color: var(--amber); }
.grade-label::after { content: ""; flex: 1; height: 1px; background: var(--line-soft); }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 0.85rem; }
.area-card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.15rem 1.25rem 1.05rem;
  text-decoration: none;
  color: var(--ink);
  transition: border-color 0.2s ease, transform 0.2s ease;
}
.area-card:hover { border-color: var(--card-color, var(--amber)); transform: translateY(-2px); }
.area-card .icon { color: var(--card-color, var(--amber)); margin-bottom: 0.5rem; }
.area-card h3 { font-family: var(--font-display); font-weight: 600; font-size: 1.12rem; margin: 0 0 0.3rem; }
.area-card p { font-size: 0.88rem; color: var(--ink-soft); margin: 0; line-height: 1.55; }

/* ---- Momentsidor: diskret etikettrad + prickar ---- */
.subnav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  margin: var(--space-md) 0 0;
}
.subnav-label {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--ink-soft);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.subnav-label .icon { color: var(--amber); }
.subnav-grade { font-weight: 400; color: var(--ink-faint); }
.dots { display: flex; }
.dots a { display: grid; place-items: center; width: 22px; height: 22px; }
.dots a::before {
  content: "";
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 2px solid var(--line);
  transition: transform 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}
.dots a:hover::before { border-color: var(--amber); transform: scale(1.25); }
.dots a.seen::before { background: var(--line); }
.dots a.active::before { background: var(--amber); border-color: var(--amber); transform: scale(1.25); }

/* ---- Innehåll ---- */
.card {
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: var(--space-lg);
  margin: var(--space-lg) 0;
}
.card > h2 {
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 4vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.15;
  margin: 0 0 0.85rem;
}
.card > h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.12rem;
  margin: var(--space-lg) 0 0.5rem;
  color: var(--amber);
}
.card p { margin: 0.6rem 0; max-width: 70ch; }
.card ul, .card ol { padding-left: 1.4rem; max-width: 68ch; }

.note {
  background: var(--amber-tint);
  border: 1px solid color-mix(in oklch, var(--amber) 30%, transparent);
  border-radius: var(--radius);
  padding: 0.85rem 1.1rem;
  margin: var(--space-md) 0;
  font-size: 0.95rem;
}
.note strong:first-child { color: var(--amber); }

.math-block {
  text-align: center;
  padding: 0.75rem 0.5rem;
  margin: 0.75rem 0;
  font-size: 1.18rem;
  overflow-x: auto;
}

/* ---- Widgets: "instrumentpanelen" ---- */
.widget {
  background: var(--bg-deep);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin: var(--space-lg) 0;
}
.widget-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--amber);
  margin: 0 0 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.widget canvas { display: block; max-width: 100%; margin: 0 auto; border-radius: 4px; }
.widget svg:not(.icon) { display: block; max-width: 100%; margin: 0 auto; }

.controls { display: flex; flex-wrap: wrap; gap: var(--space-md) var(--space-lg); margin: 0.85rem 0; }
.ctrl { display: flex; flex-direction: column; gap: 0.3rem; min-width: 160px; flex: 1; }
.ctrl label {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--ink-soft);
  display: flex;
  justify-content: space-between;
}
.ctrl label output { color: var(--amber); font-variant-numeric: tabular-nums; }
input[type="range"] {
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 2px;
  background: var(--line);
  outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--amber);
  border: 2px solid var(--bg-deep);
  cursor: grab;
}
input[type="range"]::-moz-range-thumb {
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--amber); border: 2px solid var(--bg-deep); cursor: grab;
}
input[type="range"]:focus-visible { outline: 2px solid var(--amber); outline-offset: 4px; }

.readout {
  font-variant-numeric: tabular-nums;
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 0.6rem 0.9rem;
  margin: 0.5rem 0;
  font-size: 1rem;
}

button.btn, .btn {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.5rem 1.15rem;
  border-radius: var(--radius);
  border: none;
  background: var(--amber);
  color: var(--bg-deep);
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease;
}
.btn:hover { background: var(--amber-deep); }
.btn:active { transform: scale(0.97); }
.btn.secondary { background: transparent; color: var(--ink-soft); border: 1px solid var(--line); }
.btn.secondary:hover { border-color: var(--amber); color: var(--amber); background: transparent; }

/* ---- Quiz: "utmaningen" ---- */
.quiz {
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin: var(--space-lg) 0;
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
}
.quiz-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--coral);
  margin: 0 0 0.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}
.quiz-title > span:first-child { display: inline-flex; align-items: center; gap: 0.5rem; }
.quiz-streak {
  font-size: 0.88rem;
  color: var(--amber);
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  text-transform: none;
  letter-spacing: 0;
}
.quiz-q { font-size: 1.1rem; margin: 0.5rem 0 1rem; }
.quiz-row { display: flex; flex-wrap: wrap; gap: 0.6rem; align-items: center; }
.quiz input[type="text"], .quiz input[type="number"] {
  font-family: var(--font-body);
  font-size: 1.05rem;
  color: var(--ink);
  padding: 0.5rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  width: 130px;
  background: var(--bg-deep);
}
.quiz input:focus { outline: 2px solid var(--amber); border-color: transparent; }
.quiz-feedback { margin-top: 0.85rem; padding: 0.75rem 1rem; border-radius: var(--radius); font-weight: 700; display: none; }
.quiz-feedback.ok { display: block; background: var(--green-tint); color: var(--green); }
.quiz-feedback.fail { display: block; background: var(--coral-tint); color: var(--coral); }
.quiz-choices { display: flex; flex-direction: column; gap: 0.5rem; margin: 0.75rem 0; }
.quiz-choices button {
  text-align: left;
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--ink);
  padding: 0.65rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--bg-deep);
  cursor: pointer;
}
.quiz-choices button:hover { border-color: var(--amber); }
.quiz-choices button.correct { background: var(--green-tint); border-color: var(--green); }
.quiz-choices button.wrong { background: var(--coral-tint); border-color: var(--coral); }

/* ---- Detaljer/lösningar ---- */
details.reveal {
  margin: 0.75rem 0;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: var(--bg-deep);
}
details.reveal summary {
  cursor: pointer;
  font-weight: 700;
  padding: 0.65rem 1rem;
  color: var(--sky);
  user-select: none;
}
details.reveal[open] summary { border-bottom: 1px solid var(--line-soft); }
details.reveal .reveal-body { padding: 0.75rem 1rem; }

/* ---- Tabell ---- */
table.tbl { border-collapse: collapse; width: 100%; margin: 0.75rem 0; font-size: 0.95rem; }
table.tbl th, table.tbl td { border: 1px solid var(--line-soft); padding: 0.5rem 0.75rem; text-align: left; }
table.tbl th {
  background: var(--panel-2);
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--amber);
}
table.tbl td { background: var(--bg-deep); font-variant-numeric: tabular-nums; }

/* ---- Nästa/föregående ---- */
.pagerline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: var(--space-xl);
  flex-wrap: wrap;
}
.pagerline a { text-decoration: none; font-weight: 600; display: inline-flex; align-items: center; gap: 0.45rem; }
.pagerline .prev { color: var(--ink-faint); font-size: 0.92rem; }
.pagerline .prev:hover { color: var(--amber); }
.pagerline .next {
  margin-left: auto;
  font-family: var(--font-display);
  background: var(--amber);
  color: var(--bg-deep);
  padding: 0.6rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  transition: background 0.15s ease;
}
.pagerline .next:hover { background: var(--amber-deep); }

/* KaTeX på mörk bakgrund ärver färg – men gör delningsstreck m.m. tydliga */
.katex { color: var(--ink); }

@media (max-width: 640px) {
  body { font-size: 16px; }
  .app { padding: var(--space-md) 1rem 3rem; }
  .card { padding: 1.15rem; }
  .controls { gap: 0.75rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
  html { scroll-behavior: auto; }
}