/* Reset and base styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-primary: #1a237e;
  --color-missing: #d32f2f;
  --color-due-soon: #f57f17;
  --color-test: #7b1fa2;
  --color-grade-a: #2e7d32;
  --color-grade-b: #f57f17;
  --color-grade-c: #ef6c00;
  --color-grade-d: #d84315;
  --color-grade-f: #c62828;
  --bg-light: #f5f5f5;
  --bg-white: #ffffff;
  --text-primary: #333;
  --text-secondary: #666;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.12);
  --border-radius: 12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg-light);
  color: var(--text-primary);
  line-height: 1.6;
  padding: 0;
  margin: 0;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 16px;
}

/* Header */
header {
  background: var(--color-primary);
  color: white;
  padding: 24px 20px;
  border-radius: var(--border-radius);
  margin-bottom: 20px;
  box-shadow: var(--shadow-md);
}

header h1 {
  font-size: 28px;
  font-weight: 600;
  margin: 0;
}

.timestamp {
  font-size: 14px;
  opacity: 0.9;
  margin: 8px 0 0;
}

/* Cards */
.card {
  background: var(--bg-white);
  border-radius: var(--border-radius);
  padding: 20px;
  margin-bottom: 20px;
  box-shadow: var(--shadow-sm);
}

.section-title {
  font-size: 20px;
  font-weight: 600;
  margin: 0 0 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid #e0e0e0;
}

.section-title.tests {
  color: var(--color-test);
}

.section-title.missing {
  color: var(--color-missing);
}

.section-title.due-soon {
  color: var(--color-due-soon);
}

.section-title.grades {
  color: var(--color-grade-a);
}

/* Items (assignments, tests) */
.item {
  padding: 16px;
  margin-bottom: 12px;
  border-radius: 8px;
  border-left: 4px solid;
}

.item:last-child {
  margin-bottom: 0;
}

.item-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
  line-height: 1.4;
}

.item-meta {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 10px;
}

.item-link {
  display: inline-block;
  padding: 8px 16px;
  background: var(--color-primary);
  color: white;
  text-decoration: none;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}

.item-link:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.item-link:active {
  transform: translateY(0);
}

/* Item variants */
.missing-item {
  background: #ffebee;
  border-left-color: var(--color-missing);
}

.missing-item .item-link {
  background: var(--color-missing);
}

.due-soon-item {
  background: #fffde7;
  border-left-color: var(--color-due-soon);
}

.due-soon-item .item-link {
  background: var(--color-due-soon);
}

.upcoming-test {
  background: #f3e5f5;
  border-left-color: var(--color-test);
}

.upcoming-test .item-link {
  background: var(--color-test);
}

.past-test {
  background: #ffebee;
  border-left-color: var(--color-missing);
}

.past-test .item-link {
  background: var(--color-missing);
}

/* Grades grid */
.grades-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
}

.grade-card {
  padding: 16px;
  border-radius: 8px;
  border-left: 4px solid;
  background: #f5f5f5;
}

.grade-subject {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 6px;
  line-height: 1.3;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.grade-value {
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
}

.grade-a {
  background: #f1f8e9;
  border-left-color: var(--color-grade-a);
}

.grade-a .grade-value {
  color: var(--color-grade-a);
}

.grade-b {
  background: #fffde7;
  border-left-color: var(--color-grade-b);
}

.grade-b .grade-value {
  color: var(--color-grade-b);
}

.grade-c {
  background: #fff3e0;
  border-left-color: var(--color-grade-c);
}

.grade-c .grade-value {
  color: var(--color-grade-c);
}

.grade-d, .grade-f {
  background: #ffebee;
  border-left-color: var(--color-grade-f);
}

.grade-d .grade-value, .grade-f .grade-value {
  color: var(--color-grade-f);
}

/* States */
.loading {
  text-align: center;
  padding: 40px;
  color: var(--text-secondary);
}

.error {
  padding: 20px;
  background: #ffebee;
  border-left: 4px solid var(--color-missing);
  border-radius: 8px;
  color: var(--color-missing);
}

.error-detail {
  margin-top: 8px;
  font-size: 14px;
  opacity: 0.8;
}

.all-caught-up {
  text-align: center;
  padding: 40px 20px;
}

.congrats {
  font-size: 48px;
  margin-bottom: 16px;
}

.all-caught-up p {
  font-size: 18px;
  color: var(--text-secondary);
}

/* Mobile optimizations */
@media (max-width: 600px) {
  .container {
    padding: 12px;
  }

  header {
    padding: 20px 16px;
  }

  header h1 {
    font-size: 24px;
  }

  .card {
    padding: 16px;
  }

  .section-title {
    font-size: 18px;
  }

  .item {
    padding: 14px;
  }

  .item-title {
    font-size: 15px;
  }

  .grades-grid {
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 10px;
  }

  .grade-card {
    padding: 12px;
  }
}

/* Tablet and up */
@media (min-width: 601px) {
  .container {
    padding: 24px;
  }

  header {
    padding: 28px 24px;
  }
}