:root {
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --bg-color: #0f172a;
  --surface: #1e293b;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --border: #334155;
  --error: #ef4444;
  --success: #22c55e;
  --radius: 16px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* Typography */
h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, #fff, #94a3b8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

p {
  color: var(--text-muted);
  line-height: 1.5;
}

/* Layout */
.container {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.center-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex: 1;
  text-align: center;
}

/* Upload Area */
.upload-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  width: 100%;
  margin-top: 2rem;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
  transition: var(--transition);
}

.drop-zone {
  border: 2px dashed var(--border);
  border-radius: calc(var(--radius) - 4px);
  padding: 3rem 1rem;
  cursor: pointer;
  transition: var(--transition);
  background: rgba(15, 23, 42, 0.5);
  position: relative;
}

.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.05);
}

.drop-zone svg {
  width: 48px;
  height: 48px;
  color: var(--primary);
  margin-bottom: 1rem;
}

.file-input {
  display: none;
}

/* Preview Area */
.preview-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
  display: none;
}

.preview-container.active {
  display: grid;
}

.preview-item {
  position: relative;
  aspect-ratio: 1;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.preview-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.remove-btn {
  position: absolute;
  top: 4px;
  right: 4px;
  background: rgba(0, 0, 0, 0.6);
  color: white;
  border: none;
  border-radius: 50%;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 14px;
  transition: var(--transition);
}

.remove-btn:hover {
  background: var(--error);
}

/* Buttons */
.btn {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.875rem 2rem;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  width: 100%;
  margin-top: 2rem;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
}

.btn:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 10px 20px -10px var(--primary);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

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

.btn-secondary:hover {
  background: var(--border);
  box-shadow: none;
}

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: var(--transition);
  z-index: 100;
  padding: 1rem;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: all;
}

.modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  width: 100%;
  max-width: 400px;
  transform: translateY(20px) scale(0.95);
  transition: var(--transition);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.modal-overlay.active .modal {
  transform: translateY(0) scale(1);
}

.input-group {
  margin: 1.5rem 0;
}

.input-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-muted);
}

.input-group input {
  width: 100%;
  padding: 0.875rem 1rem;
  background: var(--bg-color);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: white;
  font-size: 1rem;
  transition: var(--transition);
}

.input-group input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.modal-actions {
  display: flex;
  gap: 1rem;
}

.modal-actions .btn {
  margin-top: 0;
}

/* Progress / Status */
.status-message {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 8px;
  display: none;
}

.status-message.error {
  display: block;
  background: rgba(239, 68, 68, 0.1);
  color: var(--error);
  border: 1px solid rgba(239, 68, 68, 0.2);
}

.status-message.success {
  display: block;
  background: rgba(34, 197, 94, 0.1);
  color: var(--success);
  border: 1px solid rgba(34, 197, 94, 0.2);
}

.success-container {
  display: none;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 3rem 1rem;
}

.success-container.active {
  display: flex;
}

.success-icon {
  width: 64px;
  height: 64px;
  color: var(--success);
  margin-bottom: 1.5rem;
}

.share-link {
  background: var(--bg-color);
  border: 1px solid var(--border);
  padding: 1rem;
  border-radius: 8px;
  width: 100%;
  margin: 1.5rem 0;
  word-break: break-all;
  font-family: monospace;
  color: var(--primary);
}

/* Gallery Grid */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 1rem;
  padding: 1rem 0;
}

.gallery-item {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 1;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  transition: var(--transition);
  cursor: pointer;
  background: var(--surface);
}

.gallery-item:hover {
  transform: scale(1.03);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

/* Fullscreen Lightbox */
.lightbox {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.95);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
}

.lightbox.active {
  opacity: 1;
  pointer-events: all;
}

.lightbox img {
  max-width: 90%;
  max-height: 90vh;
  object-fit: contain;
}

.lightbox-close {
  position: absolute;
  top: 20px;
  right: 20px;
  color: white;
  background: transparent;
  border: none;
  font-size: 30px;
  cursor: pointer;
}

/* Loader */
.spinner {
  border: 3px solid rgba(255,255,255,0.3);
  border-radius: 50%;
  border-top: 3px solid white;
  width: 20px;
  height: 20px;
  -webkit-animation: spin 1s linear infinite; /* Safari */
  animation: spin 1s linear infinite;
  display: none;
}

.btn.loading .spinner {
  display: inline-block;
}

.btn.loading .btn-text {
  display: none;
}

@-webkit-keyframes spin {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-in {
  animation: fadeIn 0.5s ease-out forwards;
}