:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #adb5bd;
  --border-color: #dee2e6;
  --accent-color: #6f42c1;
  --accent-hover: #5a2d91;
  --success-color: #28a745;
  --warning-color: #ffc107;
  --danger-color: #dc3545;
  --info-color: #17a2b8;
  --shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
  --bg-primary: #1a1a1a;
  --bg-secondary: #2d2d2d;
  --bg-tertiary: #404040;
  --text-primary: #ffffff;
  --text-secondary: #b3b3b3;
  --text-muted: #808080;
  --border-color: #404040;
  --accent-color: #8b5cf6;
  --accent-hover: #7c3aed;
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --danger-color: #ef4444;
  --info-color: #06b6d4;
  --shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

body {
  font-family: 'Inter', 'Helvetica', 'Arial', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.app-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

.flex-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.flex-item {
  flex: 1;
  min-width: 250px;
}

@media (max-width: 768px) {
  html {
    font-size: 14px;
  }
}

@media (max-width: 480px) {
  html {
    font-size: 12px;
  }
}

@media (hover: none) and (pointer: coarse) {
  .nav-item, .btn, .theme-toggle, .bat-mascot {
    min-height: 44px;
    min-width: 44px;
  }
  
  .calendar-day {
    min-height: 60px;
  }
  
  .assignment-card {
    padding: 1.5rem;
  }
}

/* Device-specific styles */
.touch-device .bat-mascot:hover {
  transform: none; /* Disable hover effects on touch devices */
}

.touch-device .nav-item:hover {
  background-color: transparent;
}

.mobile .header-content {
  flex-direction: column;
  gap: 0.5rem;
}

.mobile .logo {
  flex-direction: column;
  align-items: center;
}

.mobile .header-controls {
  width: 100%;
  justify-content: space-between;
}

.tablet .main-content {
  flex-direction: column;
}

.tablet .sidebar {
  width: 100%;
  border-right: none;
  border-bottom: 1px solid var(--border-color);
}

.desktop .main-content {
  flex-direction: row;
}

.large-desktop .content-area {
  padding: 3rem;
}

@media (max-width: 768px) {
  .app-container {
    padding: 0;
  }
  
  .header {
    padding: 0.75rem 0;
  }
  
  .main-content {
    min-height: calc(100vh - 80px);
  }
}

.responsive-container {
  width: 100%;
  max-width: 100%;
  margin: 0 auto;
  padding: 0 1rem;
}

@media (min-width: 576px) {
  .responsive-container {
    padding: 0 1.5rem;
  }
}

@media (min-width: 768px) {
  .responsive-container {
    padding: 0 2rem;
  }
}

@media (min-width: 992px) {
  .responsive-container {
    padding: 0 2.5rem;
  }
}

@media (min-width: 1200px) {
  .responsive-container {
    padding: 0 3rem;
  }
}

.adaptive-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 576px) {
  .adaptive-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 768px) {
  .adaptive-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 992px) {
  .adaptive-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Rubik', 'Helvetica', 'Arial', sans-serif;
  font-weight: 500;
}

h1 {
  font-size: 2rem;
  margin-bottom: 1rem;
}

h2 {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
}

h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

h4 {
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
}

.responsive-text {
  font-size: 1rem;
}

@media (max-width: 768px) {
  .responsive-text {
    font-size: 0.875rem;
  }
  
  h1 {
    font-size: 1.75rem;
  }
  
  h2 {
    font-size: 1.375rem;
  }
  
  h3 {
    font-size: 1.125rem;
  }
}

@media (max-width: 480px) {
  .responsive-text {
    font-size: 0.75rem;
  }
  
  h1 {
    font-size: 1.5rem;
  }
  
  h2 {
    font-size: 1.25rem;
  }
  
  h3 {
    font-size: 1rem;
  }
}

.btn-responsive {
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
}

@media (max-width: 768px) {
  .btn-responsive {
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
  }
}

@media (max-width: 480px) {
  .btn-responsive {
    padding: 0.5rem 1rem;
    font-size: 0.75rem;
  }
}

.header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
  box-shadow: var(--shadow);
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: 'Rubik', 'Helvetica', 'Arial', sans-serif;
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--accent-color);
}

.logo h1 {
  margin: 0;
  line-height: 1;
  display: flex;
  align-items: center;
}

.bat-mascot {
  position: relative;
  width: 60px;
  height: 40px;
  cursor: pointer;
  transition: transform 0.3s ease;
}

.bat-mascot:hover {
  transform: scale(1.1);
}

.bat-body {
  position: absolute;
  top: 15px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 20px;
  background-color: var(--accent-color);
  border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
  z-index: 5;
}

.bat-wing {
  position: absolute;
  top: 10px;
  width: 25px;
  height: 30px;
  background-color: var(--accent-color);
  border-radius: 50% 0 0 50%;
  z-index: 2;
}


.bat-wing-left {
  left: 5px;
  transform: rotate(-20deg);
  animation: wing-flap-left 2s ease-in-out infinite;
}

.bat-wing-right {
  right: 5px;
  transform: rotate(20deg) scaleX(-1);
  animation: wing-flap-right 2s ease-in-out infinite;
}

.bat-ears {
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 6;
}

.bat-ear {
  position: absolute;
  width: 8px;
  height: 12px;
  background-color: var(--accent-color);
  border-radius: 50% 50% 0 0;
}

.bat-ear-left {
  left: -6px;
  transform: rotate(-15deg);
}

.bat-ear-right {
  right: -6px;
  transform: rotate(15deg);
}


@keyframes wing-flap-left {
  0%, 100% { transform: rotate(-20deg); }
  50% { transform: rotate(-35deg); }
}

@keyframes wing-flap-right {
  0%, 100% { transform: rotate(20deg) scaleX(-1); }
  50% { transform: rotate(35deg) scaleX(-1); }
}


@keyframes bat-float {
  0%, 100% { 
    transform: translateY(0px) rotate(0deg);
  }
  50% { 
    transform: translateY(-3px) rotate(1deg);
  }
}

.bat-mascot-small {
  position: relative;
  width: 40px;
  height: 25px;
  margin-right: 15px;
}

.bat-body-small {
  position: absolute;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  width: 12px;
  height: 12px;
  background-color: var(--accent-color);
  border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
  z-index: 5;
}

.bat-wing-small {
  position: absolute;
  top: 6px;
  width: 15px;
  height: 18px;
  background-color: var(--accent-color);
  border-radius: 50% 0 0 50%;
  z-index: 2;
}


.bat-wing-left-small {
  left: 3px;
  transform: rotate(-20deg);
  animation: wing-flap-left 2s ease-in-out infinite;
}

.bat-wing-right-small {
  right: 3px;
  transform: rotate(20deg) scaleX(-1);
  animation: wing-flap-right 2s ease-in-out infinite;
}

.bat-ears-small {
  position: absolute;
  top: 5px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 6;
}

.bat-ear-small {
  position: absolute;
  width: 5px;
  height: 8px;
  background-color: var(--accent-color);
  border-radius: 50% 50% 0 0;
}

.bat-ear-left-small {
  left: -4px;
  transform: rotate(-15deg);
}

.bat-ear-right-small {
  right: -4px;
  transform: rotate(15deg);
}


.header-controls {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
  color: var(--text-primary);
}

.theme-toggle:hover {
  background-color: var(--bg-tertiary);
  transform: scale(1.05);
}

.export-btn {
  background-color: var(--info-color);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.export-btn:hover {
  opacity: 0.9;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.add-assignment-btn {
  background-color: var(--accent-color);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.add-assignment-btn:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.main-content {
  display: flex;
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

.sidebar {
  width: 250px;
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: 2rem 0;
}

.nav-menu {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 0 1rem;
}

.nav-item {
  background: none;
  border: none;
  padding: 1rem;
  text-align: left;
  cursor: pointer;
  border-radius: 8px;
  transition: all 0.3s ease;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1rem;
  font-weight: 500;
}

.nav-item:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.nav-item.active {
  background-color: var(--accent-color);
  color: white;
}

.nav-item i {
  width: 20px;
  text-align: center;
}

.content-area {
  flex: 1;
  padding: 2rem;
  overflow-y: auto;
}

.view-container {
  display: none;
}

.view-container.active {
  display: block;
}

.calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.calendar-header h2 {
  font-size: 1.5rem;
  font-weight: 600;
}

.nav-btn {
  background: none;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.5rem;
  cursor: pointer;
  transition: all 0.3s ease;
  color: var(--text-primary);
}

.nav-btn:hover {
  background-color: var(--bg-tertiary);
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 1px;
  background-color: var(--border-color);
  border-radius: 8px;
  overflow: hidden;
}

.calendar-day {
  background-color: var(--bg-primary);
  padding: 1rem;
  min-height: 100px;
  border: none;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
}

.calendar-day:hover {
  background-color: var(--bg-secondary);
}

.calendar-day.today {
  background-color: var(--accent-color);
  color: white;
}

.calendar-day.has-events {
  background-color: var(--info-color);
  color: white;
  border: 2px solid var(--accent-color);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.calendar-day.has-events .day-number {
  font-weight: 700;
  font-size: 1.1rem;
  color: white;
}

.calendar-day-header {
  background-color: var(--bg-tertiary);
  padding: 0.75rem;
  text-align: center;
  font-weight: 600;
  color: var(--text-primary);
}

.day-number {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.day-events {
  font-size: 0.8rem;
  color: var(--text-primary);
  font-weight: 500;
  line-height: 1.2;
  margin-top: 0.25rem;
}

.day-events div {
  background-color: var(--accent-color);
  color: white;
  padding: 0.125rem 0.25rem;
  border-radius: 3px;
  margin-bottom: 0.125rem;
  font-size: 0.7rem;
  font-weight: 600;
  text-overflow: ellipsis;
  overflow: hidden;
  white-space: nowrap;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.assignments-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.filter-controls {
  display: flex;
  gap: 1rem;
}

.filter-controls select {
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

.progress-timer-section {
  margin-bottom: 2rem;
  padding: 1.5rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  box-shadow: var(--shadow);
}

.progress-timer-card {
  text-align: center;
}

.progress-timer-card h3 {
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  font-size: 1.25rem;
}

.timer-info {
  margin-bottom: 2rem;
}

.assignment-timer-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  padding: 0.75rem;
  background-color: var(--bg-tertiary);
  border-radius: 8px;
}

.assignment-timer-info span:first-child {
  font-weight: 600;
  color: var(--text-primary);
}

.assignment-timer-info span:last-child {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.timer-display-large {
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--accent-color);
  margin-bottom: 1.5rem;
  font-family: 'Rubik', 'Helvetica', 'Arial', sans-serif;
}

.progress-bar-container {
  margin-bottom: 1rem;
}

.progress-bar {
  width: 100%;
  height: 12px;
  background-color: var(--bg-tertiary);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--success-color), var(--accent-color));
  border-radius: 6px;
  transition: width 0.3s ease;
  width: 0%;
}

.progress-text {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 1.1rem;
}

.timer-controls {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.timer-controls .btn {
  min-width: 120px;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
}

.assignments-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.assignment-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  transition: all 0.3s ease;
}

.assignment-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

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

.assignment-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

.assignment-priority {
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
}

.priority-high {
  background-color: var(--danger-color);
  color: white;
}

.priority-medium {
  background-color: var(--warning-color);
  color: var(--text-primary);
}

.priority-low {
  background-color: var(--success-color);
  color: white;
}

.assignment-details {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
}

.assignment-detail {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.assignment-detail label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
}

.assignment-detail span {
  color: var(--text-primary);
}

.assignment-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
}

.btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

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

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

.btn-secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

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

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

.btn-success:hover {
  opacity: 0.9;
}

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

.btn-danger:hover {
  opacity: 0.9;
}

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

.btn-info:hover {
  opacity: 0.9;
}

.progress-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.stat-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  text-align: center;
}

.stat-card h3 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-color);
}

.grade-breakdown {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
}

.grade-breakdown h3 {
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.study-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.study-btn {
  background-color: var(--success-color);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.study-btn:hover {
  opacity: 0.9;
  transform: translateY(-2px);
}

.study-timer {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 2rem;
  text-align: center;
  margin-bottom: 2rem;
}

.timer-display {
  font-size: 3rem;
  font-weight: 500;
  color: var(--accent-color);
  margin-bottom: 1rem;
  font-family: 'Rubik', 'Helvetica', 'Arial', sans-serif;
}

.timer-controls {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.timer-btn {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
}

.timer-btn:first-child {
  background-color: var(--warning-color);
  color: var(--text-primary);
}

.timer-btn:last-child {
  background-color: var(--danger-color);
  color: white;
}

.study-sessions {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.session-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.session-info {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.session-date {
  font-weight: 600;
  color: var(--text-primary);
}

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

.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background-color: var(--bg-primary);
  border-radius: 12px;
  padding: 0;
  max-width: 500px;
  width: 90%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

.close-btn {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  transition: color 0.3s ease;
}

.close-btn:hover {
  color: var(--text-primary);
}

.assignment-form {
  padding: 1.5rem;
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent-color);
}

.form-actions {
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
  margin-top: 2rem;
}

.notification {
  position: fixed;
  top: 20px;
  right: 20px;
  background-color: var(--accent-color);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  transform: translateX(400px);
  transition: transform 0.3s ease;
  z-index: 1001;
}

.notification.show {
  transform: translateX(0);
}

.notification-content {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.notification-content i {
  animation: bat-flap 1s ease-in-out infinite;
}


@media (min-width: 1200px) {
  .header-content {
    max-width: 1400px;
  }
  
  .main-content {
    max-width: 1400px;
  }
  
  .content-area {
    padding: 3rem;
  }
  
  .calendar-grid {
    font-size: 1rem;
  }
  
  .calendar-day {
    min-height: 120px;
    padding: 1.5rem;
  }
}

@media (min-width: 992px) and (max-width: 1199px) {
  .content-area {
    padding: 2rem;
  }
  
  .calendar-day {
    min-height: 100px;
    padding: 1rem;
  }
}

@media (min-width: 768px) and (max-width: 991px) {
  .header-content {
    padding: 0 1.5rem;
  }
  
  .main-content {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    padding: 1rem 0;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .nav-menu {
    flex-direction: row;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    padding: 0 1rem;
  }
  
  .nav-item {
    flex: 1;
    min-width: 140px;
    text-align: center;
    padding: 0.75rem;
  }
  
  .content-area {
    padding: 1.5rem;
  }
  
  .calendar-grid {
    font-size: 0.9rem;
  }
  
  .calendar-day {
    min-height: 90px;
    padding: 0.75rem;
  }
  
  .assignments-header {
    flex-direction: column;
    gap: 1rem;
    align-items: stretch;
  }
  
  .filter-controls {
    flex-direction: row;
    gap: 1rem;
  }
  
  .progress-stats {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .study-header {
    flex-direction: column;
    gap: 1rem;
    align-items: stretch;
  }
  
  .timer-display {
    font-size: 2.5rem;
  }
  
  .modal-content {
    width: 90%;
    max-width: 600px;
  }
}

@media (min-width: 576px) and (max-width: 767px) {
  .header-content {
    padding: 0 1rem;
    flex-direction: column;
    gap: 1rem;
  }
  
  .header-controls {
    width: 100%;
    justify-content: space-between;
  }
  
  .main-content {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    padding: 1rem 0;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .nav-menu {
    flex-direction: row;
    overflow-x: auto;
    padding: 0 1rem;
    gap: 0.5rem;
  }
  
  .nav-item {
    white-space: nowrap;
    min-width: 120px;
    flex-shrink: 0;
  }
  
  .content-area {
    padding: 1rem;
  }
  
  .calendar-grid {
    font-size: 0.875rem;
  }
  
  .calendar-day {
    min-height: 80px;
    padding: 0.5rem;
  }
  
  .assignments-header {
    flex-direction: column;
    gap: 1rem;
    align-items: stretch;
  }
  
  .filter-controls {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .progress-stats {
    grid-template-columns: 1fr;
  }
  
  .study-header {
    flex-direction: column;
    gap: 1rem;
    align-items: stretch;
  }
  
  .timer-display {
    font-size: 2rem;
  }
  
  .modal-content {
    width: 95%;
    margin: 1rem;
  }
  
  .bat-mascot {
    width: 50px;
    height: 35px;
  }
  
  .bat-body {
    width: 16px;
    height: 16px;
  }
  
  .bat-wing {
    width: 20px;
    height: 24px;
  }
}

@media (min-width: 480px) and (max-width: 575px) {
  .header-content {
    padding: 0 0.75rem;
    flex-direction: column;
    gap: 0.75rem;
  }
  
  .logo h1 {
    font-size: 1.25rem;
  }
  
  .header-controls {
    width: 100%;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.5rem;
  }
  
  .theme-toggle {
    width: 35px;
    height: 35px;
  }
  
  .export-btn, .add-assignment-btn {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
  }
  
  .main-content {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    padding: 0.75rem 0;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .nav-menu {
    flex-direction: row;
    overflow-x: auto;
    padding: 0 0.75rem;
    gap: 0.25rem;
  }
  
  .nav-item {
    white-space: nowrap;
    min-width: 100px;
    flex-shrink: 0;
    padding: 0.5rem;
    font-size: 0.875rem;
  }
  
  .content-area {
    padding: 0.75rem;
  }
  
  .calendar-grid {
    font-size: 0.75rem;
  }
  
  .calendar-day {
    min-height: 70px;
    padding: 0.375rem;
  }
  
  .day-number {
    font-size: 0.875rem;
  }
  
  .day-events {
    font-size: 0.7rem;
  }
  
  .day-events div {
    font-size: 0.6rem;
    padding: 0.1rem 0.2rem;
  }
  
  .assignments-header {
    flex-direction: column;
    gap: 0.75rem;
    align-items: stretch;
  }
  
  .filter-controls {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .progress-stats {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  
  .stat-card {
    padding: 1rem;
  }
  
  .study-header {
    flex-direction: column;
    gap: 0.75rem;
    align-items: stretch;
  }
  
  .timer-display {
    font-size: 1.75rem;
  }
  
  .modal-content {
    width: 98%;
    margin: 0.5rem;
  }
  
  .bat-mascot {
    width: 45px;
    height: 30px;
  }
  
  .bat-body {
    width: 14px;
    height: 14px;
  }
  
  .bat-wing {
    width: 18px;
    height: 22px;
  }
}

@media (max-width: 479px) {
  .header-content {
    padding: 0 0.5rem;
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .logo {
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
  }
  
  .logo h1 {
    font-size: 1rem;
  }
  
  .header-controls {
    width: 100%;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.25rem;
  }
  
  .theme-toggle {
    width: 32px;
    height: 32px;
  }
  
  .export-btn, .add-assignment-btn {
    padding: 0.375rem 0.75rem;
    font-size: 0.75rem;
  }
  
  .main-content {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    padding: 0.5rem 0;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .nav-menu {
    flex-direction: row;
    overflow-x: auto;
    padding: 0 0.5rem;
    gap: 0.25rem;
  }
  
  .nav-item {
    white-space: nowrap;
    min-width: 80px;
    flex-shrink: 0;
    padding: 0.375rem;
    font-size: 0.75rem;
  }
  
  .nav-item i {
    width: 16px;
    font-size: 0.75rem;
  }
  
  .content-area {
    padding: 0.5rem;
  }
  
  .calendar-grid {
    font-size: 0.625rem;
  }
  
  .calendar-day {
    min-height: 60px;
    padding: 0.25rem;
  }
  
  .day-number {
    font-size: 0.75rem;
  }
  
  .day-events {
    font-size: 0.6rem;
  }
  
  .day-events div {
    font-size: 0.5rem;
    padding: 0.1rem 0.15rem;
  }
  
  .assignments-header {
    flex-direction: column;
    gap: 0.5rem;
    align-items: stretch;
  }
  
  .assignments-header h2 {
    font-size: 1.25rem;
  }
  
  .filter-controls {
    flex-direction: column;
    gap: 0.25rem;
  }
  
  .filter-controls select {
    padding: 0.375rem;
    font-size: 0.75rem;
  }
  
  .progress-stats {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  
  .stat-card {
    padding: 0.75rem;
  }
  
  .stat-card h3 {
    font-size: 0.75rem;
  }
  
  .stat-value {
    font-size: 1.5rem;
  }
  
  .study-header {
    flex-direction: column;
    gap: 0.5rem;
    align-items: stretch;
  }
  
  .study-header h2 {
    font-size: 1.25rem;
  }
  
  .timer-display {
    font-size: 1.5rem;
  }
  
  .timer-controls {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .timer-btn {
    padding: 0.5rem 1rem;
    font-size: 0.75rem;
  }
  
  .modal-content {
    width: 100%;
    margin: 0;
    border-radius: 0;
    max-height: 100vh;
  }
  
  .modal-header {
    padding: 1rem;
  }
  
  .assignment-form {
    padding: 1rem;
  }
  
  .form-actions {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .bat-mascot {
    width: 40px;
    height: 28px;
  }
  
  .bat-body {
    width: 12px;
    height: 12px;
  }
  
  .bat-wing {
    width: 16px;
    height: 20px;
  }
  
  .bat-ear {
    width: 6px;
    height: 10px;
  }
  
  .bat-eye {
    width: 3px;
    height: 3px;
  }
  
  .faq-section {
    padding: 1rem;
  }
  
  .faq-section h3 {
    font-size: 1rem;
  }
  
  .faq-item h4 {
    font-size: 0.875rem;
  }
  
  .faq-item p {
    font-size: 0.75rem;
  }
  
  .bat-speech {
    flex-direction: column;
    text-align: center;
    gap: 0.5rem;
  }
  
  .speech-bubble {
    padding: 0.75rem 1rem;
  }
  
  .speech-bubble::before {
    display: none;
  }
}

/* Ultra-wide screens (1920px+) */
@media (min-width: 1920px) {
  .header-content {
    max-width: 1800px;
  }
  
  .main-content {
    max-width: 1800px;
  }
  
  .content-area {
    padding: 4rem;
  }
  
  .calendar-day {
    min-height: 140px;
    padding: 2rem;
  }
  
  .progress-stats {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* High DPI displays */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  .bat-mascot, .bat-mascot-small {
    image-rendering: -webkit-optimize-contrast;
    image-rendering: crisp-edges;
  }
}

/* Print styles */
@media print {
  .header-controls,
  .sidebar,
  .modal {
    display: none !important;
  }
  
  .main-content {
    flex-direction: column;
  }
  
  .content-area {
    padding: 0;
  }
  
  .calendar-grid {
    break-inside: avoid;
  }
  
  .assignment-card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #000;
  }
}

/* FAQ Styles */
.faq-header {
  margin-bottom: 2rem;
}

.bat-speech {
  display: flex;
  align-items: center;
  margin-top: 1rem;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.speech-bubble {
  background-color: var(--accent-color);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: 20px;
  position: relative;
  flex: 1;
  box-shadow: var(--shadow);
}

.speech-bubble::before {
  content: '';
  position: absolute;
  left: -10px;
  top: 50%;
  transform: translateY(-50%);
  width: 0;
  height: 0;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-right: 10px solid var(--accent-color);
}

.faq-content {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.faq-section {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
}

.faq-section h3 {
  color: var(--accent-color);
  margin-bottom: 1rem;
  font-size: 1.25rem;
  font-weight: 600;
}

.faq-item {
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.faq-item:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.faq-item h4 {
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  font-size: 1rem;
  font-weight: 600;
}

.faq-item p {
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}

/* Utility Classes */
.hidden {
  display: none !important;
}

.text-center {
  text-align: center;
}

.text-muted {
  color: var(--text-muted);
}

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }