:root {
  --bg0: #e8f1ef;
  --bg1: #f7f3ea;
  --ink: #1a2b28;
  --muted: #5a6d68;
  --accent: #0f6b5c;
  --accent-2: #c45c26;
  --panel: rgba(255, 252, 247, 0.88);
  --line: rgba(26, 43, 40, 0.12);
  --danger: #a12828;
  --radius: 18px;
  --shadow: 0 18px 40px rgba(26, 43, 40, 0.08);
  --font-display: "Fraunces", Georgia, serif;
  --font-body: "Source Sans 3", "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 10% -10%, #b7ddd4 0%, transparent 55%),
    radial-gradient(900px 500px at 110% 10%, #f0d7b8 0%, transparent 50%),
    linear-gradient(160deg, var(--bg0), var(--bg1));
}

.shell {
  width: min(720px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.25rem 0 3rem;
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
}

.brand {
  font-family: var(--font-display);
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.02em;
}

h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  margin: 0 0 0.4rem;
  letter-spacing: -0.02em;
}

.lede, .meta, .progress, .ask, .hint, .empty {
  color: var(--muted);
}

.lede { margin: 0 0 1.25rem; line-height: 1.45; }

.panel, .test-list li, .card-face {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(8px);
}

.panel { padding: 1.5rem; }

.login-panel { margin-top: 12vh; }

.stack {
  display: grid;
  gap: 1rem;
}

label {
  display: grid;
  gap: 0.35rem;
  font-weight: 600;
}

label span { font-size: 0.95rem; }

input[type="text"],
input[type="password"],
input[type="number"],
input[type="file"] {
  width: 100%;
  padding: 0.75rem 0.9rem;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: #fff;
  font: inherit;
  color: var(--ink);
}

.btn, button.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.7rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  font: inherit;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
}

.btn.primary {
  background: var(--accent);
  border-color: transparent;
  color: #fff;
}

.btn.danger {
  color: var(--danger);
  background: #fff5f5;
}

.btn.wide { width: 100%; }

.linkish {
  background: none;
  border: none;
  color: var(--muted);
  font: inherit;
  cursor: pointer;
  text-decoration: underline;
  padding: 0;
}

.hero-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.test-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.test-list li {
  padding: 1rem 1.1rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
}

.test-name {
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  font-size: 1.1rem;
}

.row-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.center { text-align: center; }
.center-row { justify-content: center; }

.modes {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.85rem 1rem;
  display: grid;
  gap: 0.55rem;
}

.mode {
  display: flex;
  align-items: flex-start;
  gap: 0.55rem;
  font-weight: 500;
}

.error {
  color: var(--danger);
  background: #fff1f1;
  border: 1px solid #f0c2c2;
  padding: 0.7rem 0.9rem;
  border-radius: 12px;
}

.flash {
  list-style: none;
  margin: 0 0 1rem;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.flash li {
  padding: 0.7rem 0.9rem;
  border-radius: 12px;
  background: #e7f5ef;
  border: 1px solid #b9decd;
}

.flash li.error {
  background: #fff1f1;
  border-color: #f0c2c2;
  color: var(--danger);
}

.quiz { display: grid; gap: 1rem; }

.card-face {
  min-height: 280px;
  padding: 2rem 1.4rem;
  display: grid;
  place-content: center;
  text-align: center;
  cursor: pointer;
  transition: transform 0.25s ease, background 0.25s ease;
}

.card-face.revealed {
  background: #fff;
  transform: translateY(-2px);
}

.prompt {
  font-family: var(--font-display);
  font-size: clamp(2rem, 7vw, 3rem);
  margin: 0;
}

.answer {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 5vw, 2.3rem);
  margin: 1rem 0 0;
  color: var(--accent-2);
}

.hint { margin: 1.2rem 0 0; font-size: 0.95rem; }

.hidden { display: none !important; }

.inline { display: inline; }

.quiz-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.quiz-top .progress { margin: 0; }

.busy-overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  place-items: center;
  padding: 1.5rem;
  background: rgba(26, 43, 40, 0.45);
  backdrop-filter: blur(4px);
}

.busy-card {
  width: min(360px, 100%);
  background: #fffaf3;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.6rem 1.4rem;
  text-align: center;
}

.busy-title {
  font-family: var(--font-display);
  font-size: 1.35rem;
  margin: 1rem 0 0.35rem;
}

.busy-text {
  margin: 0;
  color: var(--muted);
  line-height: 1.4;
}

.spinner {
  width: 2.4rem;
  height: 2.4rem;
  margin: 0 auto;
  border-radius: 50%;
  border: 3px solid rgba(15, 107, 92, 0.2);
  border-top-color: var(--accent);
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@media (max-width: 560px) {
  .hero-row, .test-list li {
    flex-direction: column;
    align-items: stretch;
  }
  .row-actions .btn { flex: 1; }
}