:root {
  font-family: Nunito, "Segoe UI", sans-serif;
  color: #202d42;
  background: #f4f6fb;
  font-synthesis: none;
  --accent: #284acb;
  --accent-dark: #19359c;
  --soft: #e9edff;
  --ink: #202d42;
  --muted: #59657b;
  --line: #dce1ed;
  --paper: #fff;
}
* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; }
[hidden] { display: none !important; }
button, input { font: inherit; }
button, a { touch-action: manipulation; }
button { cursor: pointer; }
a { color: var(--accent); text-underline-offset: 3px; }
:focus-visible { outline: 3px solid #bd5e00; outline-offset: 4px; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { text-wrap: balance; line-height: 1.15; }
h1 { font-size: clamp(32px, 5vw, 46px); letter-spacing: -.035em; margin-bottom: 16px; }
h2 { font-size: 25px; margin-bottom: 12px; letter-spacing: -.025em; }
h3 { font-size: 20px; margin-bottom: 6px; }
p { line-height: 1.6; max-width: 65ch; }
header { background: var(--paper); border-bottom: 1px solid var(--line); }
.header-inner { max-width: 1120px; margin: auto; padding: 22px 28px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: flex; gap: 12px; align-items: center; font-size: 22px; font-weight: 800; }
.brand-mark { background: var(--accent); color: var(--paper); border-radius: 12px 12px 12px 3px; width: 38px; height: 40px; display: grid; place-items: center; }
.brand small { display: block; color: var(--muted); font-size: 12px; font-weight: 600; margin-top: 2px; }
main { max-width: 1120px; margin: auto; padding: 52px 28px 72px; }
.sign-in { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 400px); gap: 64px; align-items: start; }
.intro { padding-top: 24px; }
.intro p { color: var(--muted); font-size: 18px; max-width: 43ch; }
.atlas-sheet { background: var(--soft); border-radius: 20px; margin-top: 36px; max-width: 440px; padding: 30px; }
.atlas-sheet p { font-size: 16px; margin: 0; color: var(--ink); }
.atlas-sheet strong { font-size: 24px; display: block; margin-bottom: 10px; color: var(--accent-dark); }
.panel { background: var(--paper); border: 1px solid var(--line); padding: 28px; border-radius: 20px; }
.field { display: flex; flex-direction: column; gap: 8px; margin-bottom: 20px; }
label { font-weight: 700; font-size: 15px; }
input:not([type="checkbox"]) { width: 100%; min-height: 48px; border: 1px solid #929db3; border-radius: 11px; padding: 11px 13px; color: var(--ink); background: var(--paper); }
input::placeholder { color: var(--muted); }
.check { display: flex; align-items: flex-start; gap: 10px; font-weight: 500; line-height: 1.5; margin-bottom: 22px; }
input[type="checkbox"] { width: 20px; height: 20px; accent-color: var(--accent); flex-shrink: 0; margin-top: 2px; }
button { min-height: 46px; padding: 11px 18px; border-radius: 11px; background: var(--accent); color: var(--paper); border: 1px solid transparent; font-weight: 700; }
button:hover { background: var(--accent-dark); }
button:disabled { opacity: .6; cursor: wait; }
.secondary { color: var(--accent-dark); background: var(--soft); }
.secondary:hover { background: #d9e0ff; }
.outline { color: var(--ink); background: var(--paper); border-color: #929db3; }
.outline:hover { background: #f4f6fb; }
.danger { color: #942b28; background: #fff0ee; }
.danger:hover { background: #ffdfdb; }
.full { width: 100%; }
.hint { color: var(--muted); font-size: 14px; line-height: 1.6; }
.field .hint { margin: 0; }
.footnote { margin-top: 24px; margin-bottom: 0; }
.message { font-size: 15px; line-height: 1.5; margin: 18px 0; overflow-wrap: anywhere; }
.message:empty { display: none; }
.message[data-error="true"] { color: #942b28; }
.heading-row { display: flex; gap: 24px; justify-content: space-between; align-items: center; margin-bottom: 28px; }
.heading-row p { margin: 0; color: var(--muted); }
.admin-layout { display: grid; grid-template-columns: minmax(0, 1fr) 310px; gap: 32px; align-items: start; }
.learner-list { list-style: none; padding: 0; margin: 0; }
.learner-row { border-top: 1px solid var(--line); padding: 22px 0; }
.learner-row h3 { overflow-wrap: anywhere; }
.learner-row p { color: var(--muted); font-size: 14px; margin-bottom: 14px; }
.actions { display: flex; flex-wrap: wrap; gap: 10px; }
.actions button { font-size: 14px; }
.empty { padding: 32px 0; color: var(--muted); }
.credentials { margin-bottom: 28px; padding: 24px; background: var(--soft); border-radius: 14px; }
.credentials code { display: block; font-size: 20px; overflow-wrap: anywhere; padding: 12px 0 20px; user-select: all; }
.credentials p { margin-bottom: 8px; }
details { border-top: 1px solid var(--line); margin-top: 44px; padding-top: 24px; }
summary { cursor: pointer; font-size: 18px; font-weight: 700; margin-bottom: 24px; }
.password-form { max-width: 400px; }
.learning { max-width: 780px; margin: 20px auto; }
.learning .panel { padding: 40px; }
.learning .hint { margin-top: 26px; margin-bottom: 0; }
.skip-link { position: absolute; top: 8px; left: 16px; transform: translateY(-160%); padding: 12px; background: var(--paper); }
.skip-link:focus { transform: none; }
@media (max-width: 760px) {
  main { padding: 30px 20px 52px; }
  .header-inner { padding: 18px 20px; }
  .sign-in, .admin-layout { grid-template-columns: 1fr; gap: 28px; }
  .intro { padding-top: 0; }
  .intro p { font-size: 16px; }
  .atlas-sheet { display: none; }
  .panel { padding: 24px; }
  .heading-row { align-items: flex-start; }
  .admin-layout aside { grid-row: 1; }
  .learning .panel { padding: 26px; }
}
@media (prefers-reduced-motion: no-preference) {
  .credentials { animation: reveal .25s cubic-bezier(.16, 1, .3, 1); }
  @keyframes reveal { from { background-color: #c8d3ff; } to { background-color: var(--soft); } }
}