:root {
  --bg: #f7f8fb;
  --surface: #ffffff;
  --surface-strong: #ffffff;
  --ink: #1b2430;
  --muted: #6b7280;
  --line: #e2e5ec;
  --line-strong: #d3d8e2;
  --accent: #3b5bfd;
  --accent-hover: #2c47e0;
  --accent-soft: #eaeeff;
  --success: #17845a;
  --success-soft: #e6f6ee;
  --danger: #c23b3b;
  --danger-soft: #fbe9e9;
  --caret: #3b5bfd;
  --shadow: 0 10px 30px rgba(27, 36, 48, .08), 0 2px 8px rgba(27, 36, 48, .05);
  --shadow-soft: 0 6px 18px rgba(27, 36, 48, .06);
  --radius: 20px;
  --radius-small: 13px;
  color-scheme: light;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

:root[data-theme="dark"] {
  --bg: #12151c;
  --surface: #1a1e28;
  --surface-strong: #1f2430;
  --ink: #eef0f5;
  --muted: #9299a8;
  --line: #2a2f3b;
  --line-strong: #343a48;
  --accent: #6b8bff;
  --accent-hover: #839bff;
  --accent-soft: #232a44;
  --success: #3fcf8e;
  --success-soft: #163628;
  --danger: #ef6a6a;
  --danger-soft: #3a1f21;
  --caret: #6b8bff;
  --shadow: 0 10px 30px rgba(0, 0, 0, .35), 0 2px 8px rgba(0, 0, 0, .25);
  --shadow-soft: 0 6px 18px rgba(0, 0, 0, .25);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { background: var(--bg); }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 14% 0%, rgba(59, 91, 253, .06), transparent 28rem),
    var(--bg);
  transition: background-color .2s ease, color .2s ease;
}
button, input, select { font: inherit; color: inherit; }
button { -webkit-tap-highlight-color: transparent; cursor: pointer; }
a { color: inherit; }

.app-shell {
  width: min(100%, 700px);
  margin: 0 auto;
  padding: max(24px, env(safe-area-inset-top)) 16px max(32px, env(safe-area-inset-bottom));
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin: 8px 4px 22px;
}
.brand-block { display: flex; align-items: center; gap: 12px; min-width: 0; }
.brand-mark { border-radius: 10px; flex: 0 0 auto; }
.brand-overline {
  margin: 0 0 3px;
  color: var(--accent);
  font-size: .63rem;
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: .1em;
}
h1 {
  margin: 0;
  font-size: clamp(1.6rem, 6vw, 2.15rem);
  line-height: 1;
  font-weight: 750;
  letter-spacing: -.02em;
}

.topbar-actions { display: flex; align-items: center; gap: 7px; flex: 0 0 auto; }
.icon-button,
.theme-toggle,
.language-toggle {
  border: 1px solid var(--line);
  background: var(--surface);
  box-shadow: var(--shadow-soft);
  border-radius: 999px;
}
.icon-button {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  background: var(--surface);
  font-size: 1.1rem;
}
.icon-button:hover { border-color: var(--line-strong); }
.theme-toggle, .language-toggle { display: flex; padding: 3px; gap: 2px; }
.theme-option, .language-option {
  border: none;
  background: transparent;
  border-radius: 999px;
  padding: 6px 10px;
  font-size: .78rem;
  font-weight: 700;
  color: var(--muted);
  display: grid;
  place-items: center;
  min-width: 34px;
}
.theme-option[aria-checked="true"], .language-option[aria-checked="true"] {
  background: var(--accent-soft);
  color: var(--accent);
}

.level-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin: 0 4px 16px;
}
.level-pill {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  box-shadow: var(--shadow-soft);
  font-size: .92rem;
}
.level-pill-label { color: var(--muted); font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; font-weight: 700; }
.level-pill-number {
  background: var(--accent);
  color: #fff;
  font-weight: 800;
  font-size: .75rem;
  border-radius: 999px;
  padding: 2px 9px;
}
.level-nav { display: flex; gap: 6px; }

.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin: 0 4px 18px;
}
.stat {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  padding: 12px 8px;
  text-align: center;
  box-shadow: var(--shadow-soft);
}
.stat-value { display: block; font-size: clamp(1.1rem, 4vw, 1.5rem); font-weight: 800; letter-spacing: -.01em; }
.stat-label { display: block; font-size: .68rem; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; font-weight: 700; margin-top: 2px; }
.stat-best .stat-value { color: var(--accent); }

.type-area {
  background: var(--surface-strong);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 26px 24px;
  min-height: 170px;
  margin: 0 2px 14px;
  outline: none;
  position: relative;
}
.type-area:focus-visible { border-color: var(--accent); }
.type-text {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: clamp(1.05rem, 3vw, 1.35rem);
  line-height: 1.7;
  letter-spacing: .01em;
  white-space: pre-wrap;
  word-break: break-word;
}
.char { color: var(--muted); }
.char.is-correct { color: var(--ink); }
.char.is-incorrect { color: var(--danger); background: var(--danger-soft); border-radius: 3px; }
.char.is-current {
  background: var(--accent-soft);
  border-radius: 3px;
  box-shadow: inset 2px 0 0 var(--caret);
  animation: caret-blink 1s step-end infinite;
}
@keyframes caret-blink {
  0%, 100% { box-shadow: inset 2px 0 0 var(--caret); }
  50% { box-shadow: inset 2px 0 0 transparent; }
}
.type-hint {
  margin: 14px 2px 0;
  color: var(--muted);
  font-size: .85rem;
}
.skeleton {
  background: linear-gradient(90deg, var(--line) 25%, var(--line-strong) 37%, var(--line) 63%);
  background-size: 400% 100%;
  animation: skeleton-loading 1.4s ease infinite;
  border-radius: 8px;
  height: 1.4rem;
  margin-bottom: 10px;
}
.skeleton.short { width: 60%; }
@keyframes skeleton-loading {
  0% { background-position: 100% 50%; }
  100% { background-position: 0 50%; }
}

.result-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin: 0 2px 16px;
  text-align: center;
}
.result-panel h2 { margin: 0 0 14px; font-size: 1.3rem; }
.result-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-bottom: 12px; }
.result-value { display: block; font-size: 1.5rem; font-weight: 800; }
.result-label { display: block; font-size: .7rem; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; font-weight: 700; }
.result-note { color: var(--muted); font-size: .88rem; margin: 0 0 16px; }
.result-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }

.primary-button, .secondary-button {
  border: none;
  border-radius: 999px;
  padding: 11px 22px;
  font-weight: 750;
  font-size: .92rem;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.primary-button { background: var(--accent); color: #fff; }
.primary-button:hover { background: var(--accent-hover); }
.secondary-button { background: var(--surface); border: 1px solid var(--line); color: var(--ink); }
.secondary-button:hover { border-color: var(--line-strong); }

.ai-cost-note {
  text-align: center;
  color: var(--muted);
  font-size: .78rem;
  margin: 4px 4px 18px;
  min-height: 1.1em;
}

.version-mark {
  text-align: center;
  color: var(--muted);
  font-size: .74rem;
  margin: 6px 4px 0;
}
.version-separator { margin: 0 6px; }

.toast {
  position: fixed;
  left: 50%;
  bottom: 22px;
  transform: translateX(-50%);
  background: var(--ink);
  color: var(--bg);
  padding: 10px 18px;
  border-radius: 999px;
  font-size: .85rem;
  box-shadow: var(--shadow);
  z-index: 20;
}

@media (max-width: 480px) {
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .result-grid { grid-template-columns: repeat(3, 1fr); }
}

/* --- Login screen --- */
.login-screen {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}
.login-card {
  width: min(100%, 380px);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 28px;
}
.login-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  font-weight: 800;
  font-size: 1.1rem;
}
.login-brand .brand-mark { border-radius: 10px; }
.login-card h1 { margin: 0 0 6px; font-size: 1.5rem; }
.login-card > p { margin: 0 0 22px; color: var(--muted); font-size: .92rem; }
.auth-form { display: flex; flex-direction: column; gap: 14px; }
.auth-form.hidden { display: none; }
.auth-form label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: .82rem;
  font-weight: 700;
  color: var(--muted);
}
.auth-form input {
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--ink);
  border-radius: var(--radius-small);
  padding: 11px 13px;
  font-size: .95rem;
}
.auth-form input:focus-visible { outline: none; border-color: var(--accent); }
.primary-button.wide { width: 100%; justify-content: center; }
.auth-link {
  background: none;
  border: none;
  color: var(--accent);
  font-size: .85rem;
  font-weight: 700;
  text-align: center;
  padding: 4px;
}
.auth-copy { margin-bottom: 4px; }
.auth-copy h2 { margin: 0 0 4px; font-size: 1.15rem; }
.auth-copy p { margin: 0; color: var(--muted); font-size: .88rem; }
.auth-status {
  margin: 14px 0 0;
  font-size: .85rem;
  color: var(--success);
  text-align: center;
  min-height: 1.1em;
}
.auth-error {
  margin: 6px 0 0;
  font-size: .85rem;
  color: var(--danger);
  text-align: center;
  min-height: 1.1em;
  white-space: pre-line;
}

/* --- Admin view --- */
.admin-view.hidden, .hidden { display: none !important; }
.admin-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 4px 16px;
}
.admin-header h2 { margin: 0; font-size: 1.3rem; }
.admin-totals {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin: 0 2px 20px;
}
.admin-total {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  padding: 14px 10px;
  text-align: center;
  box-shadow: var(--shadow-soft);
}
.admin-total strong { display: block; font-size: 1.2rem; font-weight: 800; }
.admin-total span { display: block; font-size: .68rem; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; font-weight: 700; margin-top: 2px; }
.invite-form {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  padding: 16px;
  margin: 0 2px 8px;
  flex-wrap: wrap;
}
.invite-form label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: .8rem;
  font-weight: 700;
  color: var(--muted);
  flex: 1 1 220px;
}
.invite-form input {
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--ink);
  border-radius: var(--radius-small);
  padding: 10px 12px;
  font-size: .92rem;
}
.invite-status {
  margin: 4px 4px 20px;
  font-size: .85rem;
  color: var(--success);
  min-height: 1.1em;
}
.invite-status.error-text { color: var(--danger); }
.admin-users { display: flex; flex-direction: column; gap: 6px; margin: 0 2px; }
.admin-user-row {
  display: grid;
  grid-template-columns: 1.6fr 0.9fr 0.8fr 0.9fr 0.7fr 1fr 1.3fr;
  gap: 8px;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  padding: 10px 14px;
  font-size: .84rem;
}
.admin-user-head {
  background: transparent;
  border: none;
  box-shadow: none;
  color: var(--muted);
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .04em;
  font-weight: 700;
  padding: 0 14px;
}
.admin-user-email { font-weight: 700; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.status-pill {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: .72rem;
  font-weight: 700;
  width: fit-content;
}
.status-pill.ok { background: var(--success-soft); color: var(--success); }
.status-pill.wait { background: var(--accent-soft); color: var(--accent); }
.admin-user-actions { display: flex; gap: 6px; justify-content: flex-end; }
.secondary-button.tiny { padding: 6px 12px; font-size: .78rem; }
.secondary-button.danger { color: var(--danger); border-color: var(--danger); }

@media (max-width: 720px) {
  .admin-user-row { grid-template-columns: 1fr; text-align: left; gap: 4px; }
  .admin-user-actions { justify-content: flex-start; }
  .admin-user-head { display: none; }
}