:root {
  /* Light Theme Colors */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.95);
  --bg-accent: rgba(200, 210, 230, 0.3);

  --text-primary: #1a202c;
  --text-secondary: #4a5568;
  --text-muted: #718096;

  --border-light: #e2e8f0;
  --border-medium: #cbd5e0;
  --border-accent: #667eea;

--gradient-primary: linear-gradient(135deg, #6D5DFB 0%, #8E61D8 100%);
--gradient-success: linear-gradient(135deg, #32D89A 0%, #2BC4A0 100%);
--gradient-danger: linear-gradient(135deg, #FF6B6B 0%, #D63A3A 100%);
  --shadow-sm: 0 4px 16px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.3);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;

  --backdrop-blur: blur(10px);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}


/* ===== RESET & BASE STYLES ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  background: var(--gradient-primary);
  min-height: 100vh;
  color: var(--text-primary);
  line-height: 1.6;
  transition: var(--transition);
}


/* ===== LAYOUT COMPONENTS ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
  min-height: 100vh;
}

/* ===== HEADER SECTION ===== */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--bg-glass);
  backdrop-filter: var(--backdrop-blur);
  border-radius: var(--radius-lg);
  padding: 24px 32px;
  margin-bottom: 32px;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-light);
  transition: var(--transition);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
}

.logo i {
  font-size: 32px;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stats {
  background: var(--bg-accent);
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  color: var(--text-primary);
  border: 1px solid var(--border-accent);
}

/* ===== MAIN CONTENT ===== */
.main {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

/* ===== UPLOAD ZONE ===== */
.upload-zone {
  position: relative;
  background: var(--bg-glass);
  backdrop-filter: var(--backdrop-blur);
  border: 2px dashed var(--border-medium);
  border-radius: var(--radius-lg);
  padding: 80px 40px;
  text-align: center;
  transition: var(--transition);
  cursor: pointer;
  min-height: 320px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.upload-zone::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--gradient-primary);
  opacity: 0;
  transition: var(--transition);
  z-index: -1;
}

.upload-zone:hover {
  border-color: var(--border-accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.upload-zone:hover::before {
  opacity: 0.05;
}

.upload-zone.dragover {
  border-color: var(--border-accent);
  background: var(--bg-accent);
  transform: scale(1.02);
  box-shadow: var(--shadow-lg);
}

.upload-zone.dragover::before {
  opacity: 0.1;
}

.upload-content {
  transition: var(--transition);
  z-index: 1;
}

.upload-zone.uploading .upload-content {
  display: none;
}

.upload-icon {
  font-size: 72px;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 24px;
  animation: float 3s ease-in-out infinite;
}



.upload-zone h2 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.upload-zone p {
  font-size: 18px;
  color: var(--text-secondary);
  margin-bottom: 24px;
  max-width: 400px;
  margin-left: auto;
  margin-right: auto;
}

.browse-btn {
  background: var(--gradient-primary);
  color: white;
  border: none;
  padding: 16px 32px;
  border-radius: var(--radius-md);
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: var(--shadow-sm);
}

.browse-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 40px rgba(102, 126, 234, 0.4);
}

.browse-btn:active {
  transform: translateY(0);
}

/* ===== UPLOAD PROGRESS ===== */
.upload-progress {
  display: none;
  width: 100%;
  max-width: 400px;
  animation: fadeIn 0.5s ease;
}

.upload-zone.uploading .upload-progress {
  display: block;
}

.progress-bar {
  width: 100%;
  height: 12px;
  background: var(--bg-secondary);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 16px;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
}

.progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 6px;
  transition: width 0.3s ease;
  width: 0%;
  position: relative;
}

.progress-fill::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.3),
    transparent
  );
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  0% {
    transform: translateX(-100%);
  }
  100% {
    transform: translateX(100%);
  }
}

.progress-text {
  font-size: 16px;
  color: var(--text-secondary);
  font-weight: 600;
  text-align: center;
}

/* ===== FILES SECTION ===== */
.files-section {
  background: var(--bg-glass);
  backdrop-filter: var(--backdrop-blur);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-light);
  display: none;
}

.files-section.visible {
  display: block;
  animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 28px;
  padding-bottom: 20px;
  border-bottom: 2px solid var(--border-light);
}

.section-header h3 {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
}

.clear-btn {
  background: rgba(239, 68, 68, 0.1);
  color: #e53e3e;
  border: 1px solid rgba(239, 68, 68, 0.3);
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 8px;
}

.clear-btn:hover {
  background: rgba(239, 68, 68, 0.2);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(239, 68, 68, 0.3);
}

/* ===== FILES GRID ===== */
.files-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

.file-card {
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid var(--border-light);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.file-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--gradient-primary);
  transform: scaleX(0);
  transition: var(--transition);
}

.file-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
}

.file-card:hover::before {
  transform: scaleX(1);
}

.file-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

.file-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: white;
  font-weight: 600;
}

.file-icon.image {
  background: linear-gradient(135deg, #ff6b6b, #feca57);
}
.file-icon.document {
  background: linear-gradient(135deg, #4ecdc4, #44a08d);
}
.file-icon.video {
  background: linear-gradient(135deg, #a8edea, #fed6e3);
  color: #333;
}
.file-icon.audio {
  background: linear-gradient(135deg, #ffecd2, #fcb69f);
  color: #333;
}
.file-icon.archive {
  background: var(--gradient-primary);
}
.file-icon.other {
  background: linear-gradient(135deg, #cbd5e0, #a0aec0);
  color: #333;
}

.file-info h4 {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
  word-break: break-word;
  line-height: 1.4;
}

.file-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
}

.file-actions {
  display: flex;
  gap: 8px;
  margin-top: 20px;
}

.action-btn {
  flex: 1;
  padding: 10px 12px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.preview-btn {
  background: rgba(102, 126, 234, 0.15);
  color: #4c51bf;
  border: 1px solid rgba(102, 126, 234, 0.3);
}

.preview-btn:hover {
  background: rgba(102, 126, 234, 0.25);
  transform: translateY(-2px);
}

.download-file-btn {
  background: rgba(34, 197, 94, 0.15);
  color: #16a34a;
  border: 1px solid rgba(34, 197, 94, 0.3);
}

.download-file-btn:hover {
  background: rgba(34, 197, 94, 0.25);
  transform: translateY(-2px);
}

.delete-btn {
  background: rgba(239, 68, 68, 0.15);
  color: #e53e3e;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.delete-btn:hover {
  background: rgba(239, 68, 68, 0.25);
  transform: translateY(-2px);
}

/* ===== MODAL ===== */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(8px);
  z-index: 1000;
  animation: fadeIn 0.3s ease;
}

.modal.visible {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-content {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 900px;
  max-height: 90vh;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  animation: modalSlideIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  border: 1px solid var(--border-light);
}

@keyframes modalSlideIn {
  from {
    transform: scale(0.95) translateY(20px);
    opacity: 0;
  }
  to {
    transform: scale(1) translateY(0);
    opacity: 1;
  }
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 32px;
  border-bottom: 1px solid var(--border-light);
  background: var(--bg-glass);
}

.modal-header h3 {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
}

.close-btn {
  background: var(--bg-accent);
  border: 1px solid var(--border-light);
  font-size: 20px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 12px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
}

.close-btn:hover {
  background: var(--border-light);
  color: var(--text-primary);
  transform: scale(1.1);
}

.modal-body {
  padding: 32px;
  max-height: 60vh;
  overflow: auto;
  text-align: center;
}

.modal-body img,
.modal-body video {
  max-width: 100%;
  max-height: 500px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
}

.modal-body audio {
  width: 100%;
  margin: 24px 0;
  border-radius: var(--radius-md);
}

.modal-body pre {
  background: var(--bg-primary);
  padding: 24px;
  border-radius: var(--radius-md);
  text-align: left;
  overflow: auto;
  max-height: 400px;
  font-size: 14px;
  line-height: 1.6;
  border: 1px solid var(--border-light);
  color: var(--text-secondary);
}

.modal-footer {
  padding: 24px 32px;
  border-top: 1px solid var(--border-light);
  display: flex;
  gap: 12px;
  justify-content: flex-end;
  background: var(--bg-glass);
}

.modal-footer button {
  padding: 12px 24px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 8px;
}

.download-btn {
  background: var(--gradient-success);
  color: white;
  box-shadow: var(--shadow-sm);
}

.download-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(52, 211, 153, 0.4);
}

.share-btn {
  background: rgba(102, 126, 234, 0.15);
  color: #4c51bf;
  border: 1px solid rgba(102, 126, 234, 0.3);
}

.share-btn:hover {
  background: rgba(102, 126, 234, 0.25);
  transform: translateY(-2px);
}

/* ===== TOAST NOTIFICATIONS ===== */
.toast {
  position: fixed;
  bottom: 32px;
  right: 32px;
  background: var(--gradient-success);
  color: white;
  padding: 20px 28px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  display: none;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  z-index: 1001;
  animation: toastSlideIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  max-width: 400px;
}

@keyframes toastSlideIn {
  from {
    transform: translateX(100%) scale(0.9);
    opacity: 0;
  }
  to {
    transform: translateX(0) scale(1);
    opacity: 1;
  }
}

.toast.visible {
  display: flex;
}

.toast.error {
  background: var(--gradient-danger);
}

.toast.warning {
  background: linear-gradient(135deg, #fbbf24, #f59e0b);
}

.toast.info {
  background: var(--gradient-primary);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 1024px) {
  .files-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
}

@media (max-width: 768px) {
  .container {
    padding: 16px;
  }

  .header {
    padding: 20px 24px;
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }

  .logo {
    font-size: 24px;
  }

  .upload-zone {
    padding: 60px 24px;
    min-height: 280px;
  }

  .upload-icon {
    font-size: 56px;
  }

  .upload-zone h2 {
    font-size: 24px;
  }

  .upload-zone p {
    font-size: 16px;
  }

  .files-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .file-actions {
    flex-direction: column;
  }

  .modal-content {
    margin: 16px;
    max-height: 95vh;
  }

  .modal-body {
    padding: 24px;
  }

  .modal-footer {
    padding: 20px 24px;
    flex-direction: column;
  }

  .modal-footer button {
    width: 100%;
    justify-content: center;
  }

  .theme-toggle {
    top: 16px;
    right: 16px;
    padding: 10px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 12px;
  }

  .header {
    padding: 16px 20px;
  }

  .logo {
    font-size: 20px;
  }

  .upload-zone {
    padding: 40px 20px;
    min-height: 240px;
  }

  .upload-zone h2 {
    font-size: 20px;
  }

  .browse-btn {
    padding: 14px 24px;
    font-size: 14px;
  }

  .files-section {
    padding: 24px;
  }

  .section-header {
    flex-direction: column;
    gap: 16px;
    align-items: stretch;
  }

  .modal-header {
    padding: 20px;
  }

  .modal-body {
    padding: 20px;
  }

  .toast {
    bottom: 20px;
    right: 20px;
    left: 20px;
    max-width: none;
  }
}

/* ===== UTILITY ANIMATIONS ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes bounce {
  0%,
  20%,
  53%,
  80%,
  100% {
    transform: translate3d(0, 0, 0);
  }
  40%,
  43% {
    transform: translate3d(0, -30px, 0);
  }
  70% {
    transform: translate3d(0, -15px, 0);
  }
  90% {
    transform: translate3d(0, -4px, 0);
  }
}

.bounce {
  animation: bounce 1s ease;
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus states for accessibility */
button:focus,
.upload-zone:focus {
  outline: 2px solid var(--border-accent);
  outline-offset: 2px;
}

.action-btn:focus {
  outline: 2px solid currentColor;
  outline-offset: 2px;
}