.main-wrapper {
    background: linear-gradient(to top, #825f35, #f7941d);
    background-attachment: fixed;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Khung form */
.form-container {
    background: rgba(0,0,0,0.6);
    padding: 30px 25px;
    border-radius: 15px;
    width: 350px;
    text-align: center;
    box-shadow: 0 8px 20px rgba(0,0,0,0.3);
    color: #fff;
}

/* Tiêu đề */
.main-wrapper h1 {
    text-align: center;
    color: #fff;
    margin-bottom: 25px;
    font-size: 28px;
}

/* Label */
.form-label {
    display: block;
    text-align: left;
    margin-bottom: 5px;
    color: #f0f0f0;
    font-size: 14px;
}

/* Input fields */
.form-container input[type="text"],
.form-container input[type="email"],
.form-container input[type="password"] {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 10px;
    border: none;
    border-radius: 8px;
    background: rgba(255,255,255,0.2);
    color: #fff;
    font-size: 14px;
}

.form-container input::placeholder {
    color: #e0e0e0;
}

/* Button */
.btn-submit {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background-color: #f7941d;
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 10px;
}

.btn-submit:hover {
    background-color: #ffb347;
}

/* Validation error message */
.error-message {
    color: #ff6b6b;
    font-size: 13px;
    margin-bottom: 10px;
    text-align: left;
}

/* Login link */
.login-text {
    font-size: 14px;
    margin-top: 15px;
}

.login-text a {
    color: #f7941d;
    text-decoration: none;
}

.login-text a:hover {
    text-decoration: underline;
}

.otp-form {
    display: none;
    margin-top: 20px;
}

.otp-form input[type="text"] {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 10px;
    border: none;
    border-radius: 8px;
    background: rgba(255,255,255,0.2);
    color: #fff;
    font-size: 14px;
}

.otp-form input::placeholder {
    color: #e0e0e0;
}
/* Responsive */
@media (max-width: 400px) {
    .form-container {
        width: 90%;
        padding: 25px 15px;
    }
}
.send-otp {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background-color: #f7941d;
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.send-otp:hover {
    background-color: #ffb347;
}
.lds-dual-ring {
  display: inline-block;
  width: 64px;
  height: 64px;
}
.lds-dual-ring:after {
  content: " ";
  display: block;
  width: 46px;
  height: 46px;
  margin: 1px;
  border-radius: 50%;
  border: 5px solid #3498db;
  border-color: #3498db transparent #3498db transparent;
  animation: lds-dual-ring 1.2s linear infinite;
}
@keyframes lds-dual-ring {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}