:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --primary: #4a6cf7;
  --primary-dark: #3a56d4;
  --correct: #22a06b;
  --wrong: #e0473b;
  --text: #232838;
  --muted: #6b7280;
  --radius: 14px;
  font-family: 'Segoe UI', Roboto, Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
}

.login-body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.login-card {
  background: var(--card);
  padding: 40px;
  border-radius: var(--radius);
  box-shadow: 0 10px 30px rgba(0,0,0,0.08);
  width: 320px;
}

.login-card h1 {
  text-align: center;
  font-size: 24px;
  margin-bottom: 24px;
}

.login-card form { display: flex; flex-direction: column; gap: 14px; }
.login-card label { display: flex; flex-direction: column; font-size: 14px; color: var(--muted); gap: 6px; }
.login-card input {
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid #dfe3ec;
  font-size: 16px;
}
.login-card button {
  margin-top: 8px;
  padding: 12px;
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: white;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
}
.login-card button:hover { background: var(--primary-dark); }
.error { color: var(--wrong); font-size: 14px; min-height: 18px; text-align: center; }

/* ---------- layout ---------- */
.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: var(--card);
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  position: sticky;
  top: 0;
}
.topbar h1 { font-size: 20px; margin: 0; }
.topbar button {
  border: none;
  background: #eef1f8;
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
}
.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px 60px;
}

/* ---------- assignment cards ---------- */
.assignment-list { display: flex; flex-direction: column; gap: 12px; }
.assignment-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 18px 20px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  transition: transform 0.1s;
}
.assignment-card:hover { transform: translateY(-2px); }
.subject-badge {
  display: inline-block;
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
  background: #eef1f8;
  color: var(--primary-dark);
  margin-bottom: 6px;
}
.progress-bar {
  width: 100%;
  height: 8px;
  border-radius: 5px;
  background: #eef1f8;
  overflow: hidden;
  margin-top: 8px;
}
.progress-bar > div { height: 100%; background: var(--primary); }

/* ---------- task card ---------- */
.task-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 18px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.task-prompt { font-size: 18px; margin-bottom: 16px; font-weight: 600; }
.options { display: flex; flex-direction: column; gap: 10px; }
.option-btn {
  padding: 12px 14px;
  border-radius: 10px;
  border: 2px solid #dfe3ec;
  background: white;
  text-align: left;
  cursor: pointer;
  font-size: 16px;
}
.option-btn.selected { border-color: var(--primary); background: #eef1ff; }
.option-btn.correct { border-color: var(--correct); background: #e7f8f0; }
.option-btn.wrong { border-color: var(--wrong); background: #fdecea; }

input[type=text].answer-input, input[type=number].answer-input {
  padding: 12px 14px;
  font-size: 16px;
  border-radius: 10px;
  border: 2px solid #dfe3ec;
  width: 100%;
}

.submit-btn {
  margin-top: 16px;
  padding: 10px 20px;
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: white;
  font-weight: 600;
  cursor: pointer;
}
.submit-btn:disabled { background: #b9c2e0; cursor: not-allowed; }

.result-badge { margin-top: 12px; font-weight: 600; }
.result-badge.correct { color: var(--correct); }
.result-badge.wrong { color: var(--wrong); }
.explanation { margin-top: 6px; color: var(--muted); font-size: 14px; }

.matching-row { display: flex; gap: 10px; align-items: center; margin-bottom: 8px; }
.matching-row select { padding: 8px; border-radius: 8px; border: 1px solid #dfe3ec; font-size: 15px; }

.cloze-text { font-size: 18px; line-height: 2; }
.cloze-text input {
  width: 110px;
  padding: 4px 8px;
  border-radius: 6px;
  border: 2px solid #dfe3ec;
  font-size: 16px;
  text-align: center;
  margin: 0 4px;
}

/* ---------- parent dashboard ---------- */
.tabs { display: flex; gap: 8px; margin-bottom: 20px; }
.tabs button {
  padding: 8px 16px;
  border-radius: 8px;
  border: none;
  background: #eef1f8;
  cursor: pointer;
  font-weight: 600;
}
.tabs button.active { background: var(--primary); color: white; }

textarea#importJson {
  width: 100%;
  min-height: 220px;
  font-family: monospace;
  font-size: 13px;
  padding: 12px;
  border-radius: 10px;
  border: 1px solid #dfe3ec;
}

table.progress-table { width: 100%; border-collapse: collapse; margin-top: 10px; }
table.progress-table th, table.progress-table td {
  text-align: left;
  padding: 8px 10px;
  border-bottom: 1px solid #eef1f8;
  font-size: 14px;
}

.child-select { margin-bottom: 16px; padding: 8px 12px; border-radius: 8px; border: 1px solid #dfe3ec; }

.muted { color: var(--muted); font-size: 14px; }