body { background-color: #f0f2f5; font-family: Helvetica, Arial, sans-serif; display: flex; justify-content: center; align-items: center; height: 100vh; margin: 0; }
.signup-card { background: #ffffff; padding: 30px; border-radius: 8px; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1); width: 350px; text-align: center; }
h2 { color: #1c1e21; margin-bottom: 20px; }
input { width: 100%; padding: 14px; margin: 8px 0; border: 1px solid #dddfe2; border-radius: 6px; box-sizing: border-box; font-size: 16px; }
button { width: 100%; padding: 14px; margin-top: 10px; background-color: #000000; color: #ffffff; border: none; border-radius: 6px; font-size: 18px; font-weight: bold; cursor: pointer; transition: background 0.3s; }
button:hover { background-color: #333333; }
.error { color: #d00; font-size: 0.9em; margin-bottom: 10px; }