:root {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --accent-color: #06b6d4;
  --accent-hover: #0284c7;
  --border-color: #e2e8f0;
  --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  --input-bg: #ffffff;
  --suggestions-bg: #ffffff;
  --success-color: #22c55e;
  --success-hover: #16a34a;
  --error-color: #ef4444;
}

[data-theme="dark"] {
  --bg-primary: #0f1724;
  --bg-secondary: #1e293b;
  --text-primary: #e0e7ff;
  --text-secondary: #94a3b8;
  --accent-color: #06b6d4;
  --accent-hover: #0284c7;
  --border-color: #334155;
  --card-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
  --input-bg: #1e293b;
  --suggestions-bg: #1e293b;
  --success-color: #22c55e;
  --success-hover: #16a34a;
  --error-color: #ef4444;
}

.ytd-container * {
  box-sizing: border-box;
  transition: background-color 0.3s, color 0.3s, border-color 0.3s;
}

.ytd-container {
  font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
  margin: 0;
  padding: 1rem;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  max-width: 1200px;
  margin: 0 auto;
}

.ytd-container .header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.ytd-container h1 {
  margin: 0;
  font-size: 1.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.ytd-container .theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  border-radius: 50px;
  padding: 0.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background-color: var(--bg-secondary);
  box-shadow: var(--card-shadow);
}

.ytd-container .theme-toggle:hover {
  opacity: 0.8;
}

.ytd-container .search-box {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
  position: relative;
  width: 100%;
}

.ytd-container .search-input-wrapper {
  flex: 1;
  position: relative;
  max-width: 600px;
}

.ytd-container .search-box input {
  padding: 0.875rem 1rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  width: 100%;
  background: var(--input-bg);
  color: var(--text-primary);
  font-size: 1rem;
  box-shadow: var(--card-shadow);
}

.ytd-container .search-box input:focus {
  outline: none;
  border-color: var(--accent-color);
}

.ytd-container .search-box button {
  padding: 0.875rem 1.5rem;
  border: none;
  border-radius: 12px;
  background: var(--accent-color);
  color: #021025;
  cursor: pointer;
  font-weight: 600;
  transition: background-color 0.2s;
  white-space: nowrap;
  box-shadow: var(--card-shadow);
}

.ytd-container .search-box button:hover {
  background: var(--accent-hover);
}

.ytd-container #suggestions {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--suggestions-bg);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 0 0 12px 12px;
  max-height: 250px;
  overflow-y: auto;
  display: none;
  z-index: 10;
  box-shadow: var(--card-shadow);
}

.ytd-container #suggestions div {
  padding: 0.75rem 1rem;
  cursor: pointer;
  border-bottom: 1px solid var(--border-color);
}

.ytd-container #suggestions div:last-child {
  border-bottom: none;
}

.ytd-container #suggestions div:hover {
  background-color: var(--accent-color);
  color: #021025;
}

.ytd-container .SrForm {
  text-align: center;
  font-size: 0.55rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.ytd-container .SrForm a {
  color: var(--accent-color);
  text-decoration: none;
}

.ytd-container .SrForm a:hover {
  text-decoration: underline;
}

.ytd-container .video-result {
  background: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 16px;
  box-shadow: var(--card-shadow);
  margin-bottom: 2rem;
  animation: fadeIn 0.5s ease;
}

.ytd-container .video-result h2 {
  margin: 0 0 0.5rem 0;
  font-size: 1.25rem;
  line-height: 1.4;
}

.ytd-container .video-result p {
  margin: 0 0 0.5rem 0;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.ytd-container .video-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.ytd-container .video-info img {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  object-fit: cover;
}

.ytd-container .video-player {
  width: 100%;
  height: 0;
  padding-bottom: 56.25%; /* 16:9 aspect ratio */
  border-radius: 12px;
  margin-bottom: 1rem;
  background: #000;
  position: relative;
  overflow: hidden;
}

.ytd-container .video-player iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

.ytd-container .thumbnails {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.ytd-container .thumb {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  overflow: hidden;
  transition: transform 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0.5rem;
}

.ytd-container .thumb:hover {
  transform: translateY(-4px);
  box-shadow: var(--card-shadow);
}

.ytd-container .thumb img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 8px;
}

.ytd-container .thumb label {
  display: flex;
  align-items: center;
  margin-top: 0.5rem;
  font-size: 0.75rem;
  cursor: pointer;
  text-align: center;
  color: var(--text-secondary);
  gap: 0.25rem;
}

.ytd-container .thumb input[type="checkbox"] {
  margin: 0;
}

.ytd-container .download-all {
  display: block;
  margin: 2rem auto;
  padding: 0.875rem 1.5rem;
  background: var(--success-color);
  color: #021025;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 600;
  transition: background-color 0.2s;
  box-shadow: var(--card-shadow);
}

.ytd-container .download-all:hover {
  background: var(--success-hover);
}

.ytd-container .download-all:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.ytd-container .pagination {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 2rem;
}

.ytd-container .pagination button {
  padding: 0.75rem 1.25rem;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  background: var(--accent-color);
  color: #021025;
  font-weight: 600;
  transition: background-color 0.2s;
  box-shadow: var(--card-shadow);
}

.ytd-container .pagination button:hover:not(:disabled) {
  background: var(--accent-hover);
}

.ytd-container .pagination button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.ytd-container .loading {
  text-align: center;
  padding: 2rem;
  font-size: 1.125rem;
  color: var(--accent-color);
}

.ytd-container .error {
  text-align: center;
  padding: 1.5rem;
  color: var(--error-color);
  background: var(--bg-secondary);
  border-radius: 12px;
  margin: 1rem 0;
  box-shadow: var(--card-shadow);
}

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

/* Mobile-first responsive design */
@media (max-width: 640px) {
  .ytd-container {
    padding: 1rem 0.75rem;
  }
  
  .ytd-container .header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }
  
  .ytd-container h1 {
    font-size: 1.5rem;
  }
  
  .ytd-container .search-box {
    flex-direction: column;
  }
  
  .ytd-container .search-input-wrapper {
    width: 100%;
  }
  
  .ytd-container .search-box button {
    width: 100%;
    margin-top: 0.5rem;
  }
  
  .ytd-container .video-result {
    padding: 1rem;
    border-radius: 12px;
  }
  
  .ytd-container .video-result h2 {
    font-size: 1.125rem;
  }
  
  .ytd-container .thumbnails {
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    gap: 0.75rem;
  }
  
  .ytd-container .thumb label {
    font-size: 0.6875rem;
  }
  
  .ytd-container .download-all {
    width: 100%;
    margin: 1.5rem auto;
  }
  
  .ytd-container .pagination {
    flex-wrap: wrap;
  }
  
  .ytd-container .pagination button {
    flex: 1;
    min-width: 120px;
  }
}

@media (min-width: 641px) and (max-width: 1024px) {
  .ytd-container {
    padding: 1.5rem;
  }
  
  .ytd-container .thumbnails {
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  }
}

/* Dark mode toggle icon adjustments */
.ytd-container .theme-toggle svg {
  width: 20px;
  height: 20px;
  fill: var(--text-primary);
}

/* Focus styles for accessibility */
.ytd-container button:focus-visible,
.ytd-container input:focus-visible {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}