/* Base styles */
:root {
  --primary: #3B82F6;
  --primary-dark: #1E40AF;
  --background: #F9FAFB;
  --card-bg: #FFFFFF;
  --text-primary: #1F2937;
  --text-secondary: #6B7280;
  --border-color: #E5E7EB;
  --success: #10B981;
  --warning: #F59E0B;
  --danger: #EF4444;
  --radius: 0.5rem;
  --box-shadow: 0 2px 10px 0 rgba(0, 0, 0, 0.05);
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--background);
  color: var(--text-primary);
  line-height: 1.5;
}

a {
  color: var(--primary);
  text-decoration: none;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.layout {
  display: flex;
  height: 100vh;
}

.sidebar {
  width: 250px;
  height: 100vh;
  position: fixed;
  background-color: var(--card-bg);
  box-shadow: var(--box-shadow);
  z-index: 50;
  overflow-y: auto;
  transition: transform 0.3s ease;
}

.sidebar-header {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-user {
  padding: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.user-avatar {
  width: 40px;
  height: 40px;
  background-color: rgba(59, 130, 246, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}

.main-content {
  flex: 1;
  margin-left: 250px;
  padding: 2rem;
  overflow-y: auto;
}

.mobile-header {
  display: none;
  padding: 1rem;
  background-color: var(--card-bg);
  box-shadow: var(--box-shadow);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 40;
  align-items: center;
  justify-content: space-between;
}

/* Components */
.logo {
  display: flex;
  align-items: center;
}

.logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  margin-left: 0.5rem;
}

.card {
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1.125rem;
  font-weight: 600;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 1rem;
  font-weight: 500;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background-color: var(--primary);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-dark);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.btn-outline:hover {
  background-color: var(--background);
}

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: 50%;
}

.nav-menu {
  list-style: none;
  padding: 1rem 0;
}

.nav-item {
  margin-bottom: 0.5rem;
}

.nav-link {
  display: flex;
  align-items: center;
  padding: 0.75rem 1rem;
  color: var(--text-primary);
  font-weight: 500;
  border-radius: var(--radius);
  transition: all 0.2s ease;
}

.nav-link:hover {
  background-color: var(--background);
}

.nav-link.active {
  background-color: var(--primary);
  color: white;
}

.nav-icon {
  margin-right: 0.75rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.25rem 0.5rem;
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: 9999px;
}

.badge-success {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--success);
}

.badge-warning {
  background-color: rgba(245, 158, 11, 0.1);
  color: var(--warning);
}

.badge-danger {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--danger);
}

.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-cols-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
  grid-template-columns: repeat(3, 1fr);
}

.footer {
  text-align: center;
  padding: 1.5rem 0;
  color: var(--text-secondary);
  font-size: 0.875rem;
  border-top: 1px solid var(--border-color);
  margin-top: 2rem;
}

/* Login page */
.login-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--background);
}

.login-card {
  width: 100%;
  max-width: 400px;
  padding: 2rem;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--box-shadow);
}

.login-header {
  text-align: center;
  margin-bottom: 2rem;
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.form-label {
  font-weight: 500;
  font-size: 0.875rem;
}

.form-input {
  padding: 0.65rem 0.75rem;
  font-size: 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  width: 100%;
  transition: border-color 0.2s ease;
}

.form-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.1);
}

/* Subject card */
.subject-card {
  display: flex;
  flex-direction: column;
  padding: 1.5rem;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--box-shadow);
  height: 100%;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  cursor: pointer;
}

.subject-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 15px 0 rgba(0, 0, 0, 0.07);
}

.subject-color {
  width: 3rem;
  height: 3rem;
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
  color: white;
}

.subject-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.subject-info {
  display: flex;
  align-items: center;
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: auto;
}

/* Homework list */
.homework-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.homework-item {
  display: flex;
  padding: 1rem;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  border-left: 4px solid var(--primary);
  box-shadow: var(--box-shadow);
}

.homework-content {
  flex: 1;
}

.homework-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.homework-meta {
  display: flex;
  gap: 1rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.homework-description {
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.homework-actions {
  display: flex;
  gap: 0.5rem;
  margin-left: 1rem;
}

/* Announcement list */
.announcement-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.announcement-item {
  padding: 1rem;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--box-shadow);
}

.announcement-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.5rem;
}

.announcement-title {
  font-weight: 600;
}

.announcement-date {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.announcement-content {
  font-size: 0.875rem;
}

/* Material list */
.material-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.material-item {
  display: flex;
  padding: 1rem;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--box-shadow);
}

.material-icon {
  margin-right: 1rem;
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.material-content {
  flex: 1;
}

.material-title {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.material-description {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* Responsive */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    width: 100%;
  }
  
  .sidebar.active {
    transform: translateX(0);
  }
  
  .main-content {
    margin-left: 0;
    padding-top: 5rem;
  }
  
  .mobile-header {
    display: flex;
  }
  
  .grid-cols-2, .grid-cols-3 {
    grid-template-columns: 1fr;
  }
}