body {
    font-family: 'Poppins', sans-serif;
    background: #f0f2f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.registration-container {
    background: white;
    padding: 2.5em;
    border-radius: 12px;
    box-shadow: 0 0 30px rgba(0, 0, 0, 0.1);
    text-align: center;
    max-width: 400px;
    width: 100%;
}

.input-container {
    position: relative;
    margin-bottom: 15px;
}

.input-container .hint {
    text-align: left;
    padding-left: 15px;
    color: #6c757d;
    font-size: 11px;
    margin-top: 4px;
    line-height: 1.4;
}

.input-container.error .hint {
    display: none;   /* ซ่อน hint เมื่อมี error ขึ้น เพื่อไม่ให้ซ้อน */
}


.input-container input:focus {
    border-color: #007BFF;
    outline: none;
}


.input-container .icon {
    position: absolute;
    left: 15px;
    top: 35%;
    transform: translateY(-50%);
    color: #888;
}

.input-container.success input {
    border-color: #09c372;
}

.input-container.error input {
    border-color: #ff3860;
}

.input-container .error {
    text-align: left;
    padding-left: 15px;
    color: red;
    font-size: 12px;
    font-weight: 400;
    margin-top: 4px;
    min-height: 0;
}

.input-container input {
    width: 100%;
    padding: 15px 15px 15px 45px;
    border: 1px solid #ddd;
    border-radius: 30px;
    box-sizing: border-box;
    font-size: 16px;
    font-family: 'Poppins', sans-serif;
    transition: border-color 0.3s;
}

.verify-button {
    width: 100%;
    padding: 15px;
    border: none;
    border-radius: 30px;
    font-size: 16px;
    cursor: pointer;
    margin-bottom: 15px;
    background-color: #007BFF;
    color: white;
    font-weight: 600;
    transition: background 0.3s;
}

.verify-button:hover {
    background-color: #0056b3;
}

.verify-button:disabled {
    background-color: #6c8ebf;
    cursor: not-allowed;
}

/* Inline spinner ในปุ่ม */
.btn-spinner {
    display: inline-block;
    width: 14px;
    height: 14px;
    border: 2px solid rgba(255, 255, 255, 0.4);
    border-top-color: #fff;
    border-radius: 50%;
    animation: btn-spin 0.8s linear infinite;
    vertical-align: middle;
    margin-right: 6px;
}

@keyframes btn-spin {
    to { transform: rotate(360deg); }
}

.back-to-login {
    left: 20px;
    top: 20px;
    font-size: 20px;
    color: #007BFF;
    text-decoration: none;
    display: flex;
    align-items: center;
}

.back-to-login i {
    margin-right: 5px;
}

.back-to-login:hover {
    color: #0056b3;
}

@media (max-width: 768px) {
    .registration-container {
        padding: 2em;
    }

    .input-container input {
        padding: 12px 12px 12px 40px;
    }

    .verify-button {
        padding: 12px;
        font-size: 14px;
    }
}