.flex
{
    display: flex;
}
.flex-column
{
    flex-direction: column;
}
.juCenter
{
    justify-content: center;
}
.items
{
    align-items: center;
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}


.container {
    max-width: 500px;
    width: 100%;
    background: white;
    border-radius: 20px;
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    animation: fadeIn 0.8s ease-out;
}

.header {
    background: linear-gradient(135deg, #4b6cb7 0%, #182848 100%);
    color: white;
    padding: 30px 40px;
    text-align: center;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
}

.header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.content {
    padding: 40px;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: #333;
    font-size: 1.1rem;
}

.input-group {
    display: flex;
    gap: 10px;
}

.captcha-container {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 12px;
    border: 1px solid #e9ecef;
}
@media (max-width: 576px)
{
    .captcha-container
    {
        padding: 4px;
    }
}

.captcha-box {
    flex: 1;
    height: 60px;
    background: #f8f9fa;
    border-radius: 8px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 28px;
    font-weight: bold;
    letter-spacing: 5px;
    color: #182848;
    border: 1px solid #dee2e6;
    position: relative;
    overflow: hidden;
    user-select: none;
}

.captcha-box::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, 
        transparent 49%, rgba(0,0,0,0.1) 50%, 
        transparent 51%, transparent 99%, rgba(0,0,0,0.1) 100%);
    background-size: 20px 20px;
    opacity: 0.3;
}

.captcha-box::after {
    content: "";
    position: absolute;
    top: -10px;
    left: -10px;
    right: -10px;
    bottom: -10px;
    background: repeating-linear-gradient(
        -45deg,
        transparent,
        transparent 10px,
        rgba(0,0,0,0.05) 10px,
        rgba(0,0,0,0.05) 20px
    );
    z-index: -1;
}

.refresh-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: #4b6cb7;
    color: white;
    border: none;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(75, 108, 183, 0.3);
}

.refresh-btn:hover {
    background: #3a5795;
    transform: rotate(90deg);
}

.refresh-btn:active {
    transform: rotate(270deg) scale(0.95);
}

input[type="text"] {
    width: 100%;
    padding: 15px 20px;
    border: 2px solid #e9ecef;
    border-radius: 12px;
    font-size: 1.1rem;
    transition: all 0.3s ease;
}

input[type="text"]:focus {
    border-color: #4b6cb7;
    outline: none;
    box-shadow: 0 0 0 4px rgba(75, 108, 183, 0.2);
}

.submit-btn {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, #4b6cb7 0%, #182848 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 10px 20px rgba(75, 108, 183, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.submit-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 25px rgba(75, 108, 183, 0.4);
}

.submit-btn:active {
    transform: translateY(1px);
}

.message {
    margin-top: 20px;
    padding: 15px;
    border-radius: 10px;
    text-align: center;
    font-weight: 500;
    display: none;
    animation: fadeIn 0.5s ease;
}

.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
    display: block;
}

.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
    display: block;
}

.footer {
    text-align: center;
    padding: 20px;
    color: #6c757d;
    font-size: 0.9rem;
    border-top: 1px solid #e9ecef;
}

.footer a {
    color: #4b6cb7;
    text-decoration: none;
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    10%, 30%, 50%, 70%, 90% { transform: translateX(-5px); }
    20%, 40%, 60%, 80% { transform: translateX(5px); }
}

.shake {
    animation: shake 0.5s ease;
}

/* 响应式设计 */
@media (max-width: 576px) {
    .header {
        padding: 25px 20px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .content {
        padding: 30px 20px;
    }
    
    .captcha-container {
        flex-direction: column;
    }
    
    .captcha-box {
        width: 100%;
    }
}