body {
    margin: 0;
    padding: 0;
    font-family: 'Comic Sans MS', 'Comic Sans', cursive, sans-serif;
    background: #f3f1ee;
    color: #212529;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    text-align: center;
  }
  
  .main-header {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #f3f1ee;
    border-bottom: 3px solid #222;
    box-shadow: 0 4px 0 #222;
    padding: 8px 32px;
    margin-bottom: 32px;
    min-height: 64px;
  }
  
  .header-left {
    display: flex;
    align-items: center;
  }
  
  .header-logo {
    height: 100px;
    width: auto;
    margin-right: 502px;
  }
  
  .header-right {
    display: flex;
    gap: 16px;
    align-items: center;
  }
  
  .login-btn, .register-btn {
    background: #46baf7;
    color: #222;
    border: 2px solid #222;
    border-radius: 8px;
    padding: 8px 20px;
    font-weight: bold;
    text-decoration: none;
    box-shadow: 2px 2px 0px #222;
    transition: background 0.2s, color 0.2s, box-shadow 0.2s;
  }
  
  .login-btn:hover, .register-btn:hover {
    background: #222;
    color: #fff;
    box-shadow: 1px 1px 0px #222;
  }
  
  nav {
    width: 100%;
    background: white;
    border-bottom: 3px solid black;
    box-shadow: 0px 4px 0px black;
    padding: 10px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: bold;
  }
  
  nav .nav-left {
    font-size: 1.2rem;
  }
  
  nav .nav-right a {
    margin-left: 20px;
    text-decoration: none;
    color: black;
    border: 2px solid black;
    padding: 6px 12px;
    box-shadow: 2px 2px 0px black;
    transition: all 0.2s ease-in-out;
  }
  
  nav .nav-right a:hover {
    transform: scale(1.05);
    background: #f1f1f1;
  }
  
  .logo-center {
    display: flex;
    justify-content: center;
    margin-bottom: 40px;
  }
  
  .logo-center img {
    width: 250px;
    height: auto;
    display: block;
    margin: 0 auto;
    border-radius: 8px;
  }
  
  h2 {
    font-size: 2.5rem;
    background: white;
    padding: 10px 20px;
    border: 3px solid black;
    box-shadow: 4px 4px 0px black;
    display: inline-block;
    font-weight: bold;
    text-transform: uppercase;
    margin-bottom: 40px;
  }
  
  .buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
  }
  
  .button {
    display: inline-block;
    border: 2px solid black;
    background: #46baf7;
    color: black;
    text-decoration: none;
    padding: 8px 24px;
    border-radius: 8px;
    font-size: 1em;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    font-weight: 500;
    box-shadow: 4px 4px 0px black;
    cursor: pointer;
  }
  
  .button:hover {
    transform: scale(1.05);
    background: #222;
    color: #fff;
    box-shadow: 2px 2px 0px black;
  }
  
  .cards-container {
    display: flex;
    gap: 48px;
    justify-content: center;
    align-items: flex-start;
    flex-wrap: wrap;
  }
  
  .test-card {
    background: #fff;
    border: 2px solid #222;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.03);
    width: 250px;
    min-height: 340px;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 24px 16px 20px 16px;
    margin-bottom: 24px;
    transition: box-shadow 0.2s, border-color 0.2s, background 0.2s;
  }
  
  .test-card:hover {
    box-shadow: 10px 20px 24px rgba(0,0,0,0.15);
    border-color: #000000;
    background: #f5faff;
  }
  
  .test-card img {
    max-width: 180px;
    max-height: 180px;
    width: auto;
    height: auto;
    display: block;
    margin: 0 auto 16px auto;
    object-fit: contain;
  }
  
  .test-card h3 {
    font-size: 1.3em;
    margin: 0 0 10px 0;
    font-family: inherit;
    text-align: center;
  }
  
  .test-card p {
    font-size: 1em;
    margin: 0 0 24px 0;
    text-align: left;
    width: 100%;
    color: #222;
    line-height: 1.4;
  }
  
  @media (max-width: 600px) {
    h2 {
      font-size: 1.8rem;
      padding: 8px 12px;
    }
    .button {
      font-size: 1rem;
      padding: 10px 20px;
    }
    .logo-center img {
      max-width: 80%;
    }
    nav {
      flex-direction: column;
      gap: 10px;
    }
  }
  
  @media (max-width: 900px) {
    .cards-container {
      flex-direction: column;
      align-items: center;
      gap: 32px;
    }
  }
  .back-button {
    position: absolute;
    top: 20px;
    left: 20px;
    text-decoration: none;
    background-color: #ffffff;
    border: 3px solid black;
    padding: 10px 18px;
    font-weight: bold;
    color: #000;
    box-shadow: 4px 4px 0 black;
    text-transform: uppercase;
    transition: background-color 0.2s ease;
  }
  
  .back-button:hover {
    background-color: #e9ecef;
  }
.alert {
  padding: 16px 24px;
  margin: 20px auto 30px auto;
  border-radius: 10px;
  max-width: 400px;
  text-align: center;
  font-weight: 600;
  box-shadow: 3px 3px 0 rgba(0,0,0,0.1);
}

.alert.error {
  background-color: #ffe0e0;
  border: 2px solid #b20000;
  color: #b20000;
  box-shadow: 3px 3px 0 #b20000;
}

.alert.success {
  background-color: #d4edda;
  border: 2px solid green;
  color: #155724;
  box-shadow: 3px 3px 0 green;
}