:root {
  --bg: #f5f7ff;
  --card: #ffffff;
  --text: #1f2a44;
  --accent: #3a73ff;
  --accent-2: #2a56c7;
  --error: #b3261e;
  --success: #1b7f3b;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Inter", "Segoe UI", sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, #eef2ff, var(--bg));
}

.container {
  width: min(900px, 94%);
  margin: 2rem auto;
}

h1, h2 { margin-top: 0; }
.subtitle { margin-bottom: 1.5rem; }

.card-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.card {
  background: var(--card);
  border-radius: 16px;
  padding: 1.2rem;
  box-shadow: 0 8px 20px rgba(31, 42, 68, 0.08);
  text-decoration: none;
  color: inherit;
}

.assignment-card { display: flex; flex-direction: column; gap: 0.4rem; }
.assignment-detail { margin-bottom: 1rem; }
.form-card { display: grid; gap: 0.75rem; }

label { font-weight: 600; }
input, textarea {
  width: 100%;
  border: 1px solid #c9d4f2;
  border-radius: 10px;
  padding: 0.65rem;
  font-size: 1rem;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 500;
}

.checkbox-row input { width: auto; }

.button {
  display: inline-block;
  border: none;
  border-radius: 12px;
  background: var(--accent);
  color: #fff;
  padding: 0.7rem 1rem;
  font-weight: 700;
  text-decoration: none;
  text-align: center;
  cursor: pointer;
}

.button:hover { background: var(--accent-2); }
.button.big { font-size: 1.1rem; padding: 0.9rem 1.1rem; }

.success { border-left: 6px solid var(--success); }
.error { border-left: 6px solid var(--error); }
.back-link { display: inline-block; margin-bottom: 1rem; }

@media (max-width: 600px) {
  .container { margin-top: 1rem; }
  .card { padding: 1rem; }
}