/* practice-online v2 — student-facing styles.
   Its own visual system, deliberately not the hub's theme, same as v1.
   Mobile-first: most students reach this on a phone or a Chromebook. */

:root {
  --bg: #eef1f8;
  --surface: #ffffff;
  --ink: #1b2233;
  --ink-soft: #5b6479;
  --line: #d7deeb;
  --accent: #2b5cd9;
  --accent-ink: #ffffff;
  --danger: #b3261e;
  --danger-bg: #fdeceb;
  --ok: #1a7f4b;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(16, 24, 44, .06), 0 8px 24px rgba(16, 24, 44, .07);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11151f;
    --surface: #1a2130;
    --ink: #e8ecf5;
    --ink-soft: #9aa4b8;
    --line: #2c3547;
    --accent: #6f9bff;
    --accent-ink: #0d1220;
    --danger: #ff9b93;
    --danger-bg: #3a1d1b;
    --ok: #6bd39b;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px rgba(0, 0, 0, .35);
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100dvh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: clamp(16px, 5vw, 48px) 16px;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
}

.card {
  width: 100%;
  max-width: 420px;
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: clamp(20px, 5vw, 32px);
}
.card.wide { max-width: 680px; }

h1 { font-size: 22px; margin: 0 0 4px; letter-spacing: -.01em; }
h2 { font-size: 17px; margin: 24px 0 8px; }
p  { margin: 0 0 16px; }
.sub { color: var(--ink-soft); font-size: 14px; margin: 0 0 24px; }

label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  margin: 0 0 6px;
  color: var(--ink-soft);
  letter-spacing: .02em;
  text-transform: uppercase;
}

input {
  width: 100%;
  font: inherit;
  padding: 12px 14px;
  margin: 0 0 18px;
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
}
input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  border-color: var(--accent);
}
/* PIN and code fields: big, spaced characters, numeric keypad on phones. */
input.chunky {
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 24px;
  letter-spacing: .3em;
  text-align: center;
  padding: 14px;
}

button {
  width: 100%;
  font: inherit;
  font-weight: 600;
  padding: 13px 16px;
  border: 1px solid var(--accent);
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-ink);
  cursor: pointer;
}
button:disabled { opacity: .5; cursor: default; }
button.ghost {
  background: transparent;
  color: var(--accent);
  border-color: var(--line);
  font-weight: 500;
}
button.link {
  background: none;
  border: none;
  color: var(--accent);
  text-decoration: underline;
  padding: 10px 0 0;
  font-weight: 500;
  width: auto;
}
.row { display: flex; gap: 10px; }
.row > button { flex: 1; }

.msg {
  border-radius: 8px;
  padding: 11px 13px;
  font-size: 14px;
  margin: 0 0 18px;
}
.msg.error { background: var(--danger-bg); color: var(--danger); }
.msg.ok    { background: transparent; color: var(--ok); border: 1px solid var(--ok); }

.hint { font-size: 13px; color: var(--ink-soft); margin: -10px 0 18px; }

.whoami {
  display: flex; align-items: baseline; justify-content: space-between;
  gap: 12px; margin: 0 0 20px; padding: 0 0 16px;
  border-bottom: 1px solid var(--line);
}
.whoami .name { font-weight: 700; font-size: 18px; }
.whoami .meta { color: var(--ink-soft); font-size: 13px; }

.empty {
  border: 1px dashed var(--line);
  border-radius: 8px;
  padding: 22px 18px;
  text-align: center;
  color: var(--ink-soft);
  font-size: 14px;
}

.spinner {
  width: 18px; height: 18px; margin: 40px auto;
  border: 2px solid var(--line); border-top-color: var(--accent);
  border-radius: 50%; animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .spinner { animation-duration: 2s; } }