:root {
    --primary: #4361ee;
    --primary-hover: #3a56d4;
    --secondary: #4cc9f0;
    --dark: #292f36;
    --light: #ffffff;
    --gray-light: #f8f9fa;
    --gray: #e9ecef;
    --error: #ef476f;
    --success: #06d6a0;
    --border-radius: 12px;
    --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --transition: all 0.3s ease;
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Roboto', system-ui, -apple-system, sans-serif;
  }
  
  body {
    background-color: var(--gray-light);
    color: var(--dark);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
  }
  
  .container {
    width: 100%;
    max-width: 550px;
    background-color: var(--light);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
  }
  
  .header {
    padding: 25px 30px;
    background-color: var(--light);
    border-bottom: 1px solid var(--gray);
  }
  
  .header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--dark);
    display: flex;
    align-items: center;
    gap: 10px;
  }
  
  .header h1 i {
    color: var(--primary);
  }
  
  .content {
    padding: 30px;
  }
  
  .input-group {
    position: relative;
    margin-bottom: 20px;
  }
  
  .input-group input {
    width: 100%;
    padding: 15px 20px;
    padding-left: 45px;
    background-color: var(--gray-light);
    border: 2px solid transparent;
    border-radius: var(--border-radius);
    font-size: 1rem;
    color: var(--dark);
    transition: var(--transition);
  }
  
  .input-group input:focus {
    outline: none;
    border-color: var(--primary);
    background-color: var(--light);
    box-shadow: 0 5px 15px rgba(67, 97, 238, 0.1);
  }
  
  .input-group i {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: #adb5bd;
    font-size: 1.2rem;
  }
  
  .input-group input:focus + i {
    color: var(--primary);
  }
  
  button.download-btn {
    width: 100%;
    padding: 15px;
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
  }
  
  button.download-btn:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(67, 97, 238, 0.2);
  }
  
  .result {
    margin-top: 30px;
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition);
  }
  
  .result.active {
    opacity: 1;
    transform: translateY(0);
  }
  
  .result-card {
    background-color: var(--gray-light);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  }
  
  .video-info {
    padding: 20px;
  }
  
  .video-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 10px;
    line-height: 1.4;
  }
  
  .thumbnail {
    width: 100%;
    aspect-ratio: 16/9;
    object-fit: cover;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
  }
  
  .download-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin-top: 15px;
  }
  
  .download-options a {
    text-decoration: none;
  }
  
  .quality-btn {
    padding: 10px;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    font-size: 0.9rem;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
  }
  
  .sd-btn {
    background-color: var(--gray);
    color: var(--dark);
  }
  
  .sd-btn:hover {
    background-color: #dde2e6;
  }
  
  .hd-btn {
    background-color: var(--secondary);
    color: var(--light);
  }
  
  .hd-btn:hover {
    background-color: #3ab8dd;
  }
  
  .loader {
    display: none;
    text-align: center;
    padding: 20px;
  }
  
  .loader .spinner {
    width: 40px;
    height: 40px;
    margin: 0 auto;
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-left-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
  }
  
  @keyframes spin {
    100% {
      transform: rotate(360deg);
    }
  }
  
  .error-message {
    color: var(--error);
    background-color: rgba(239, 71, 111, 0.1);
    padding: 15px;
    border-radius: var(--border-radius);
    text-align: center;
    margin-top: 20px;
    display: none;
  }
  
  /* Responsive adjustments */
  @media (max-width: 480px) {
    .container {
      border-radius: 0;
    }
    
    .download-options {
      grid-template-columns: 1fr;
    }
  }
  
  /* Success animation */
  .success-checkmark {
    display: none;
    justify-content: center;
    margin-bottom: 20px;
  }
  
  .check-icon {
    width: 60px;
    height: 60px;
    position: relative;
    border-radius: 50%;
    box-sizing: content-box;
    border: 4px solid var(--success);
  }
  
  .check-icon::before {
    content: "";
    position: absolute;
    top: 50%;
    left: 25%;
    transform: rotate(-45deg);
    transform-origin: 20% 65%;
    width: 10%;
    height: 25%;
    background-color: var(--success);
    animation: checkmark-first 0.4s ease forwards;
  }
  
  .check-icon::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 28%;
    transform: rotate(40deg);
    transform-origin: 100% 100%;
    width: 40%;
    height: 10%;
    background-color: var(--success);
    animation: checkmark-second 0.4s ease forwards;
  }
  
  @keyframes checkmark-first {
    0% {
      width: 0;
      height: 0;
      opacity: 1;
    }
    100% {
      width: 10%;
      height: 25%;
      opacity: 1;
    }
  }
  
  @keyframes checkmark-second {
    0% {
      width: 0;
      height: 0;
      opacity: 1;
    }
    100% {
      width: 40%;
      height: 10%;
      opacity: 1;
    }
  }
  
  @keyframes shake {
    0%, 100% { transform: translateX(0); }
    10%, 30%, 50%, 70%, 90% { transform: translateX(-5px); }
    20%, 40%, 60%, 80% { transform: translateX(5px); }
  }
  
  /* Footer styles */
  .footer {
    margin-top: 20px;
    text-align: center;
    color: #6c757d;
    font-size: 0.9rem;
  }
  
  .footer a {
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition);
  }
  
  .footer a:hover {
    color: var(--primary-hover);
  }