:root {
  /* Light Theme Colors */
  --primary-color: #667eea;
  --secondary-color: #764ba2;
  --accent-color: #f093fb;
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --error-color: #ef4444;
  
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-overlay: rgba(255, 255, 255, 0.1);
  
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-light: #94a3b8;
  
  --border-color: rgba(226, 232, 240, 0.5);
  --shadow-light: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-medium: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-heavy: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  
  --blur-sm: blur(8px);
  --blur-md: blur(16px);
}

[data-theme="dark"] {
  /* Dark Theme Colors */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: rgba(30, 41, 59, 0.85);
  --bg-overlay: rgba(0, 0, 0, 0.2);
  
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-light: #64748b;
  
  --border-color: rgba(51, 65, 85, 0.5);
  --shadow-light: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-medium: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
  --shadow-heavy: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  min-height: 100vh;
  transition: all 0.3s ease;
}

/* Authentication Styles */
.auth-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  position: relative;
}

.auth-card {
  background: var(--bg-card);
  backdrop-filter: var(--blur-md);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 3rem;
  max-width: 400px;
  width: 100%;
  box-shadow: var(--shadow-heavy);
  position: relative;
  overflow: hidden;
}

.auth-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
  border-radius: 20px 20px 0 0;
}

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

.logo-section {
  text-align: left;
  flex: 1;
}

.logo-section i {
  font-size: 2.5rem;
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
  display: block;
}

.logo-section h1 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo-section p {
  color: var(--text-secondary);
  font-size: 0.85rem;
}

.auth-theme-toggle {
  background: var(--bg-overlay);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 0.6rem;
  cursor: pointer;
  transition: all 0.3s ease;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

.auth-theme-toggle:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-light);
  background: var(--bg-secondary);
}

.auth-theme-toggle i {
  font-size: 1rem;
}

.auth-form {
  display: none;
  animation: fadeIn 0.5s ease;
}

.auth-form.active {
  display: block;
}

.auth-form h2 {
  text-align: center;
  margin-bottom: 2rem;
  color: var(--text-primary);
  font-weight: 600;
}

.input-group {
  position: relative;
  margin-bottom: 1.5rem;
}

.input-group i {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  z-index: 2;
}

.input-group input {
  width: 100%;
  padding: 1rem 1rem 1rem 3rem;
  border: 2px solid var(--border-color);
  border-radius: 12px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 1rem;
  transition: all 0.3s ease;
}

.input-group input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.toggle-password {
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 1rem;
  z-index: 2;
}

.validation-icon {
  position: absolute;
  right: 3rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1rem;
}

.validation-icon.valid {
  color: var(--success-color);
}

.validation-icon.invalid {
  color: var(--error-color);
}

.password-strength {
  margin-top: -1rem;
  margin-bottom: 1.5rem;
}

.strength-meter {
  height: 4px;
  background: var(--border-color);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.strength-fill {
  height: 100%;
  width: 0%;
  transition: all 0.3s ease;
  border-radius: 2px;
}

.strength-text {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.auth-btn {
  width: 100%;
  padding: 1rem;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  border: none;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.auth-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-medium);
}

.auth-switch {
  text-align: center;
  margin-top: 2rem;
}

.auth-switch p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.auth-switch a {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 600;
  cursor: pointer;
  transition: color 0.3s ease;
}

.auth-switch a:hover {
  color: var(--secondary-color);
}

/* Dashboard Styles */
.dashboard-container {
  min-height: 100vh;
  background: var(--bg-primary);
}

.dashboard-header {
  background: var(--bg-card);
  backdrop-filter: var(--blur-md);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: var(--shadow-light);
  position: sticky;
  top: 0;
  z-index: 100;
  gap: 1rem;
}

.header-left .logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary-color);
}

.header-center {
  flex: 1;
  text-align: center;
}

.header-center h1 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-shrink: 0;
}

.theme-toggle {
  background: var(--bg-overlay);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 0.6rem;
  cursor: pointer;
  transition: all 0.3s ease;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

.theme-toggle:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-light);
  background: var(--bg-secondary);
}

.theme-toggle i {
  font-size: 1rem;
}

.logout-btn {
  background: linear-gradient(135deg, var(--error-color), #dc2626);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 0.5rem 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  white-space: nowrap;
  flex-shrink: 0;
}

.logout-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-light);
}

.dashboard-main {
  padding: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

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

.stat-card {
  background: var(--bg-card);
  backdrop-filter: var(--blur-sm);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow: var(--shadow-light);
  transition: all 0.3s ease;
}

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

.stat-icon {
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  color: white;
  width: 50px;
  height: 50px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.stat-content h3 {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.stat-content p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.storage-meter {
  flex-direction: column;
  align-items: stretch;
}

.storage-progress {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}

.progress-bar {
  flex: 1;
  height: 8px;
  background: var(--border-color);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--success-color), var(--primary-color));
  border-radius: 4px;
  transition: width 0.5s ease;
  width: 0%;
}

/* Tab Navigation */
.tab-navigation {
  display: flex;
  background: var(--bg-card);
  backdrop-filter: var(--blur-sm);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 0.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-light);
}

.tab-btn {
  flex: 1;
  background: none;
  border: none;
  padding: 1rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.tab-btn:hover {
  background: var(--bg-overlay);
  color: var(--text-primary);
}

.tab-btn.active {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  box-shadow: var(--shadow-light);
}

/* Tab Content */
.tab-content {
  min-height: 400px;
}

.tab-pane {
  display: none;
  animation: fadeIn 0.5s ease;
}

.tab-pane.active {
  display: block;
}

/* Welcome Section */
.welcome-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.welcome-card, .rules-card {
  background: var(--bg-card);
  backdrop-filter: var(--blur-sm);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: var(--shadow-light);
}

.welcome-icon {
  background: linear-gradient(135deg, var(--success-color), var(--primary-color));
  color: white;
  width: 60px;
  height: 60px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  margin-bottom: 1rem;
}

.welcome-card h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.welcome-card p {
  color: var(--text-secondary);
  line-height: 1.7;
}

.rules-card h3 {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--warning-color);
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

.rules-card ul {
  list-style: none;
  padding: 0;
}

.rules-card li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.rules-card li i {
  color: var(--success-color);
  margin-top: 0.2rem;
  flex-shrink: 0;
}

/* Upload Section */
.upload-section {
  display: grid;
  gap: 2rem;
}

.upload-card {
  background: var(--bg-card);
  backdrop-filter: var(--blur-sm);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: var(--shadow-light);
}

.upload-zone {
  border: 2px dashed var(--border-color);
  border-radius: 12px;
  padding: 3rem 2rem;
  text-align: center;
  transition: all 0.3s ease;
  cursor: pointer;
  position: relative;
}

.upload-zone:hover, .upload-zone.dragover {
  border-color: var(--primary-color);
  background: rgba(102, 126, 234, 0.05);
}

.upload-icon {
  font-size: 3rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.upload-zone h3 {
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.upload-zone p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.upload-zone input[type="file"] {
  display: none;
}

.browse-btn {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.5rem;
  cursor: pointer;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 500;
}

.browse-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-light);
}

.supported-formats {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.supported-formats h4 {
  color: var(--text-primary);
  margin-bottom: 1rem;
  font-weight: 600;
}

.format-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.format-tag {
  background: var(--bg-overlay);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

/* File Preview */
.file-preview {
  background: var(--bg-card);
  backdrop-filter: var(--blur-sm);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: var(--shadow-light);
}

.file-preview.hidden {
  display: none;
}

.file-preview h3 {
  color: var(--text-primary);
  margin-bottom: 1rem;
  font-weight: 600;
}

.preview-list {
  display: grid;
  gap: 1rem;
  margin-bottom: 2rem;
}

.preview-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background: var(--bg-overlay);
  border: 1px solid var(--border-color);
  border-radius: 8px;
}

.preview-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  color: white;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.preview-info {
  flex: 1;
}

.preview-info h4 {
  color: var(--text-primary);
  font-weight: 500;
  margin-bottom: 0.25rem;
  font-size: 0.9rem;
}

.preview-info p {
  color: var(--text-secondary);
  font-size: 0.8rem;
}

.upload-btn {
  width: 100%;
  background: linear-gradient(135deg, var(--success-color), var(--primary-color));
  color: white;
  border: none;
  border-radius: 12px;
  padding: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 1rem;
}

.upload-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-medium);
}

/* Files Section */
.files-section {
  background: var(--bg-card);
  backdrop-filter: var(--blur-sm);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: var(--shadow-light);
}

.files-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.search-bar {
  position: relative;
  flex: 1;
  min-width: 250px;
}

.search-bar i {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
}

.search-bar input {
  width: 100%;
  padding: 0.75rem 1rem 0.75rem 2.5rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  transition: all 0.3s ease;
}

.search-bar input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.sort-controls select {
  padding: 0.75rem 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.3s ease;
}

.sort-controls select:focus {
  outline: none;
  border-color: var(--primary-color);
}

.files-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.file-card {
  background: var(--bg-overlay);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

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

.file-card.locked::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(2px);
  z-index: 1;
}

.file-card.locked .lock-overlay {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 2;
  text-align: center;
}

.file-card.locked .lock-overlay i {
  font-size: 2rem;
  color: var(--warning-color);
  margin-bottom: 0.5rem;
}

.file-card.locked .unlock-btn {
  background: var(--warning-color);
  color: white;
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1rem;
  cursor: pointer;
  font-size: 0.8rem;
  transition: all 0.3s ease;
}

.file-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.file-icon {
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
}

.file-info h4 {
  color: var(--text-primary);
  font-weight: 600;
  margin-bottom: 0.25rem;
  font-size: 1rem;
  line-height: 1.2;
}

.file-info p {
  color: var(--text-secondary);
  font-size: 0.8rem;
}

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

.file-btn {
  flex: 1;
  padding: 0.5rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  font-size: 0.8rem;
  font-weight: 500;
}

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

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

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

.file-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-light);
}

.no-files {
  grid-column: 1 / -1;
  text-align: center;
  padding: 3rem;
  color: var(--text-secondary);
}

.no-files i {
  font-size: 3rem;
  margin-bottom: 1rem;
  color: var(--text-light);
}

.no-files h3 {
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

/* Modal Styles */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: 1000;
  animation: fadeIn 0.3s ease;
}

.modal.active {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.modal-content {
  background: var(--bg-card);
  backdrop-filter: var(--blur-md);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  max-width: 400px;
  width: 100%;
  box-shadow: var(--shadow-heavy);
  animation: slideUp 0.3s ease;
}

.modal-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1.5rem 2rem 1rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-header i {
  font-size: 1.5rem;
  color: var(--primary-color);
}

.modal-header h3 {
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1.2rem;
}

.modal-body {
  padding: 2rem;
}

.modal-body p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.pin-options {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.radio-option {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.radio-option input[type="radio"] {
  accent-color: var(--primary-color);
}

.checkbox-option {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 1rem;
}

.checkbox-option input[type="checkbox"] {
  accent-color: var(--primary-color);
}

.modal-footer {
  display: flex;
  gap: 1rem;
  padding: 1rem 2rem 2rem;
}

.btn-primary, .btn-secondary {
  flex: 1;
  padding: 0.75rem 1rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 500;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
}

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

.btn-primary:hover, .btn-secondary:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-light);
}

.attempts-warning {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  border-radius: 8px;
  padding: 0.75rem;
  margin-top: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--error-color);
  font-size: 0.9rem;
}

.attempts-warning.hidden {
  display: none;
}

/* Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes slideUp {
  from {
    transform: translateY(20px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .auth-container {
    padding: 1rem;
  }
  
  .auth-card {
    padding: 2rem;
  }

  .auth-header {
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    text-align: center;
  }

  .logo-section {
    text-align: center;
  }
  
  .dashboard-header {
    padding: 1rem;
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .header-left, .header-center, .header-right {
    width: 100%;
    justify-content: center;
  }

  .header-right {
    flex-direction: row;
    justify-content: center;
    gap: 1rem;
  }
  
  .header-center h1 {
    font-size: 1.2rem;
  }
  
  .dashboard-main {
    padding: 1rem;
  }
  
  .storage-stats {
    grid-template-columns: 1fr;
  }
  
  .tab-navigation {
    flex-direction: column;
  }
  
  .tab-btn {
    justify-content: flex-start;
  }
  
  .welcome-section {
    grid-template-columns: 1fr;
  }
  
  .files-header {
    flex-direction: column;
    align-items: stretch;
  }
  
  .search-bar {
    min-width: auto;
  }
  
  .files-grid {
    grid-template-columns: 1fr;
  }
  
  .modal-content {
    margin: 1rem;
    max-width: none;
  }
  
  .modal-header, .modal-body, .modal-footer {
    padding: 1rem 1.5rem;
  }
}

@media (max-width: 480px) {
  .logo-section h1 {
    font-size: 1.5rem;
  }
  
  .upload-zone {
    padding: 2rem 1rem;
  }
  
  .upload-icon {
    font-size: 2rem;
  }
  
  .format-tags {
    justify-content: center;
  }
  
  .file-actions {
    flex-direction: column;
  }
  
  .pin-options {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .modal-footer {
    flex-direction: column;
  }
}

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

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

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }