:root {
  --bg: #0e1116;
  --bg-soft: #161b22;
  --bg-elev: #1c232c;
  --border: #2b3440;
  --text: #e6edf3;
  --muted: #8b98a5;
  --accent: #4f9cf9;
  --accent-soft: #1f3b5c;
  --good: #3fb950;
  --good-soft: #16351f;
  --bad: #f85149;
  --bad-soft: #3d1a1a;
  --warn: #d29922;
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f8fa;
    --bg-soft: #ffffff;
    --bg-elev: #ffffff;
    --border: #d8dee4;
    --text: #1f2328;
    --muted: #59636e;
    --accent: #0969da;
    --accent-soft: #ddf4ff;
    --good: #1a7f37;
    --good-soft: #dafbe1;
    --bad: #cf222e;
    --bad-soft: #ffebe9;
    --shadow: 0 6px 20px rgba(31, 35, 40, 0.12);
  }
}

* { box-sizing: border-box; }

html, body { margin: 0; }

body {
  background: var(--bg);
  color: var(--text);
  -webkit-text-size-adjust: 100%;
  min-height: 100dvh;
}

button { font: inherit; color: inherit; cursor: pointer; }
input, select, textarea { font: inherit; }
.hidden { display: none !important; }

/* ---- header ---- */
.app-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.6rem 1rem;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--text);
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 1.8rem;
  height: 1.8rem;
  border-radius: 9px;
  background: var(--accent);
  color: #fff;
  font-size: 0.95rem;
}

.nav {
  display: flex;
  gap: 0.25rem;
  margin-left: auto;
}

.nav button {
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 0.5rem 0.8rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.nav button:hover { color: var(--text); background: var(--bg-elev); }
.nav button.active { color: var(--text); background: var(--accent-soft); }

.header-right { display: flex; align-items: center; gap: 0.6rem; }

.streak-chip {
  font-variant-numeric: tabular-nums;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.35rem 0.7rem;
  font-size: 0.85rem;
}

/* ---- layout ---- */
main {
  max-width: 880px;
  margin: 0 auto;
  padding: 1.2rem 1rem 4rem;
}

.view { animation: fade 0.18s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; } }

.card {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem;
  box-shadow: var(--shadow);
}

.card + .card { margin-top: 1rem; }

h1, h2, h3 { margin: 0 0 0.6rem; line-height: 1.2; }
h2 { font-size: 1.15rem; }
.muted { color: var(--muted); }
.small { font-size: 0.85rem; }

/* ---- buttons & fields ---- */
.btn {
  border: 1px solid var(--border);
  background: var(--bg-elev);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.95rem;
  font-weight: 600;
  transition: transform 0.05s ease, background 0.15s ease;
}
.btn:hover { background: color-mix(in srgb, var(--bg-elev) 80%, var(--accent)); }
.btn:active { transform: scale(0.98); }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-primary:hover { background: color-mix(in srgb, var(--accent) 85%, #fff); }
.btn-ghost { background: transparent; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-block { width: 100%; }

.field { display: grid; gap: 0.3rem; margin-bottom: 0.8rem; font-size: 0.9rem; }
.field > span { color: var(--muted); }

input, select {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.7rem;
  width: 100%;
}
input:focus, select:focus, .btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 0.8rem;
}
.control-actions { display: flex; gap: 0.6rem; flex-wrap: wrap; margin-top: 1rem; }

.segmented { display: flex; gap: 0.3rem; flex-wrap: wrap; }
.segmented button {
  border: 1px solid var(--border);
  background: var(--bg);
  border-radius: 999px;
  padding: 0.4rem 0.8rem;
  font-size: 0.85rem;
}
.segmented button.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* ---- drill session ---- */
.session-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.6rem;
  font-variant-numeric: tabular-nums;
}
.pill {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.25rem 0.7rem;
  font-size: 0.85rem;
}
.pill.time { color: var(--warn); }
.pill.time.danger { color: var(--bad); }

.timer-track { height: 6px; border-radius: 999px; background: var(--bg-elev); overflow: hidden; }
.timer-fill { height: 100%; width: 100%; background: var(--accent); transition: width 0.1s linear; }
.timer-fill.danger { background: var(--bad); }

.prompt {
  font-size: clamp(1.8rem, 6vw, 3rem);
  font-weight: 700;
  text-align: center;
  margin: 1.6rem 0 0.4rem;
  line-height: 1.25;
  word-break: break-word;
}
.prompt-sub { text-align: center; color: var(--muted); min-height: 1.2em; }

.answer-input {
  font-size: clamp(1.4rem, 5vw, 2rem);
  text-align: center;
  padding: 0.7rem;
  margin-top: 0.6rem;
}

.feedback {
  text-align: center;
  font-weight: 700;
  min-height: 1.6rem;
  margin-top: 0.8rem;
}
.feedback.correct { color: var(--good); }
.feedback.wrong { color: var(--bad); }

.card-correct { border-color: var(--good); box-shadow: 0 0 0 1px var(--good) inset; }
.card-wrong { border-color: var(--bad); box-shadow: 0 0 0 1px var(--bad) inset; }

/* ---- result table ---- */
.result-list { display: grid; gap: 0.4rem; margin-top: 0.8rem; }
.result-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  padding: 0.5rem 0.7rem;
  border-radius: var(--radius-sm);
  background: var(--bg-elev);
  font-size: 0.9rem;
}
.result-row.ok { background: var(--good-soft); }
.result-row.no { background: var(--bad-soft); }
.result-row .mark { font-weight: 700; }

/* ---- stats grid ---- */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 0.8rem;
  margin-top: 0.6rem;
}
.stat {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.9rem;
}
.stat .value { font-size: 1.7rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.stat .label { color: var(--muted); font-size: 0.82rem; }

/* ---- profile cards ---- */
.profile-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 0.8rem;
  margin-top: 0.8rem;
}
.profile {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.8rem;
}
.profile h3 { font-size: 1rem; margin-bottom: 0.4rem; }
.profile dl { margin: 0; display: grid; grid-template-columns: auto 1fr; gap: 0.15rem 0.6rem; font-size: 0.85rem; }
.profile dt { color: var(--muted); }
.profile dd { margin: 0; }

.countdown {
  font-size: clamp(2.4rem, 9vw, 4rem);
  font-weight: 800;
  text-align: center;
  font-variant-numeric: tabular-nums;
  margin: 1rem 0;
}
.countdown.ready { color: var(--good); }

/* ---- memory questions ---- */
.choice-grid { display: grid; gap: 0.5rem; margin-top: 1rem; }
.choice {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  text-align: left;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  border-radius: var(--radius-sm);
  padding: 0.8rem 1rem;
  font-size: 1.05rem;
}
.choice:hover { border-color: var(--accent); }
.choice.selected { border-color: var(--accent); background: var(--accent-soft); }
.choice .key {
  display: grid;
  place-items: center;
  width: 1.6rem;
  height: 1.6rem;
  border-radius: 7px;
  background: var(--bg);
  border: 1px solid var(--border);
  font-size: 0.85rem;
  font-weight: 700;
  flex: none;
}
.match-row { display: grid; grid-template-columns: 1fr 1.2fr; gap: 0.6rem; align-items: center; margin-bottom: 0.5rem; }

/* ---- chart ---- */
.chart { width: 100%; height: auto; margin-top: 0.8rem; }
.chart .bar { fill: var(--accent); opacity: 0.85; }
.chart .bar:hover { opacity: 1; }
.chart .axis { stroke: var(--border); }
.chart .label { fill: var(--muted); font-size: 9px; }
.chart .line { fill: none; stroke: var(--good); stroke-width: 2; }
.chart .dot { fill: var(--good); }

/* ---- dialog ---- */
.dialog {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-soft);
  color: var(--text);
  padding: 0;
  width: min(92vw, 380px);
  box-shadow: var(--shadow);
}
.dialog::backdrop { background: rgba(0, 0, 0, 0.55); }
.dialog-form { padding: 1.2rem; }
.dialog-actions { display: flex; justify-content: flex-end; gap: 0.6rem; margin-top: 0.6rem; }
.tabs { display: flex; gap: 0.4rem; margin-bottom: 1rem; }
.tab {
  flex: 1;
  border: 1px solid var(--border);
  background: var(--bg);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
}
.tab.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.form-error { color: var(--bad); min-height: 1.2em; font-size: 0.85rem; margin: 0.4rem 0 0; }

/* ---- toasts ---- */
.toasts { position: fixed; bottom: 1rem; left: 50%; transform: translateX(-50%); display: grid; gap: 0.5rem; z-index: 50; }
.toast {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 0.7rem 0.9rem;
  box-shadow: var(--shadow);
  animation: fade 0.15s ease;
  max-width: 90vw;
}
.toast.good { border-left-color: var(--good); }
.toast.bad { border-left-color: var(--bad); }

@media (max-width: 560px) {
  .brand span:last-child { display: none; }
  .nav button { padding: 0.5rem 0.6rem; }
  .header-right { gap: 0.4rem; }
  .streak-chip { padding: 0.3rem 0.5rem; }
  .match-row { grid-template-columns: 1fr; }
}

/* ---- language toggle & link buttons ---- */
#lang-button { min-width: 2.6rem; font-size: 0.8rem; letter-spacing: 0.05em; }
.link-button {
  display: block;
  width: 100%;
  margin-top: 0.5rem;
  border: 0;
  background: none;
  color: var(--accent);
  font-size: 0.85rem;
  text-align: center;
}
.link-button:hover { text-decoration: underline; }

/* ---- recovery code ---- */
.recovery-code {
  display: block;
  margin: 0.7rem 0;
  padding: 0.8rem;
  background: var(--bg-elev);
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
  font-size: 1.25rem;
  letter-spacing: 0.12em;
  text-align: center;
  word-break: break-all;
  user-select: all;
}

/* ---- inline hint banner ---- */
.hint {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  margin-top: 0.8rem;
  padding: 0.7rem 0.8rem;
  background: var(--accent-soft);
  border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
}
.hint p { margin: 0; flex: 1; }
.hint button {
  border: 0;
  background: none;
  color: var(--accent);
  font-size: 0.8rem;
  white-space: nowrap;
  text-decoration: underline;
}

.session-head .btn { padding: 0.3rem 0.6rem; font-size: 0.85rem; }

/* ---- nav on small screens ---- */
.nav { overflow-x: auto; scrollbar-width: none; -ms-overflow-style: none; }
.nav::-webkit-scrollbar { display: none; }

/* ---- reaction test ---- */
.reaction-pad {
  margin-top: 1rem;
  width: 100%;
  min-height: 240px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--muted);
  display: grid;
  place-items: center;
  font-size: clamp(1.6rem, 6vw, 2.6rem);
  font-weight: 800;
  user-select: none;
  cursor: pointer;
  transition: background 0.08s ease, color 0.08s ease;
}
.reaction-pad.go { background: var(--good); border-color: var(--good); color: #fff; }
.reaction-pad.soon { background: var(--bad); border-color: var(--bad); color: #fff; }
.reaction-pad.done { cursor: default; }

/* ---- visual memory grid ---- */
.grid-board {
  display: grid;
  gap: 6px;
  margin: 1rem auto 0;
  width: 100%;
  max-width: 420px;
}
.grid-cell {
  aspect-ratio: 1 / 1;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  transition: background 0.1s ease, transform 0.05s ease;
}
.grid-cell.on { background: var(--accent); border-color: var(--accent); }
.grid-cell.clickable { cursor: pointer; }
.grid-cell.clickable:hover { transform: scale(0.95); }
.grid-cell.selected { outline: 3px solid var(--warn); outline-offset: -3px; }
.grid-cell.correct { background: var(--good); border-color: var(--good); }
.grid-cell.wrong { background: var(--bad); border-color: var(--bad); }
.grid-cell.missed { outline: 3px solid var(--good); outline-offset: -3px; }

/* ---- equal-width segmented controls ---- */
.segmented { display: flex; gap: 0.3rem; flex-wrap: wrap; }
.segmented button { flex: 1 1 0; min-width: 2.6rem; padding: 0.45rem 0.4rem; text-align: center; }

/* ---- range slider ---- */
input[type="range"] {
  width: 100%;
  padding: 0;
  border: 0;
  background: transparent;
  accent-color: var(--accent);
}

/* ---- on-screen math keypad ---- */
.keypad {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  margin: 1rem auto 0;
  max-width: 340px;
}
.keypad .key {
  min-height: 3rem;
  padding: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  border-radius: var(--radius-sm);
}
.keypad .key:active { transform: scale(0.97); background: var(--accent-soft); }
.keypad .key-enter {
  grid-column: 1 / -1;
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* ---- settings menu dialog ---- */
.dialog-form .btn-block + .btn-block { margin-top: 0.6rem; }

/* ---- mobile header: separate nav row, account/language behind settings ---- */
.menu-button { display: none; }

@media (max-width: 700px) {
  .app-header { flex-wrap: wrap; row-gap: 0.4rem; padding-bottom: 0.5rem; }
  #lang-button,
  #auth-button { display: none; }
  .menu-button { display: inline-block; }
  .nav { order: 3; width: 100%; margin-left: 0; }
  .header-right { margin-left: auto; }
}

/* ---- session head: wrap instead of overflowing (long German labels) ---- */
.session-head { flex-wrap: wrap; gap: 0.5rem; }
.session-head .pill { font-size: 0.9rem; min-width: 0; }
.session-head .btn { flex: none; }
@media (max-width: 520px) {
  .pill-cat { display: none; }
}

/* ---- visual memory: timer below the board, fixed height so nothing shifts ---- */
#visual-countdown {
  min-height: 1.8rem;
  margin: 0.7rem 0 0;
  font-size: 1.7rem;
}