* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #000000;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow: hidden;
}

/* 背景装饰元素 */
body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

/* 蓝色圆圈 - 左上角 */
body::after {
    content: '';
    position: fixed;
    top: 30px;
    left: 30px;
    width: 60px;
    height: 60px;
    background: #4A90E2;
    border-radius: 50%;
    z-index: 0;
}

.login-container {
    width: 100%;
    max-width: 450px;
    padding: 20px;
    position: relative;
    z-index: 10;
}

.login-box {
    background: transparent;
    border-radius: 0;
    padding: 0;
    box-shadow: none;
}

.login-box h1 {
    display: none;
}

.login-box h2 {
    display: none;
}

.error-message {
    background: rgba(255, 0, 0, 0.2);
    color: #ff4444;
    padding: 10px;
    border-radius: 5px;
    margin-bottom: 20px;
    text-align: center;
    font-size: 14px;
    border: 1px solid rgba(255, 68, 68, 0.3);
}

.form-group {
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.form-group label {
    color: #ffffff;
    font-size: 14px;
    font-weight: 500;
    min-width: 70px;
    text-align: right;
}

.form-group input {
    flex: 1;
    padding: 12px 15px;
    background: #ffffff;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    color: #333;
    transition: all 0.3s;
}

.form-group input:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.2);
}

.captcha-group {
    display: flex;
    gap: 10px;
    align-items: center;
    flex: 1;
}

.captcha-group input {
    flex: 1;
}

.captcha-image {
    width: 120px;
    height: 40px;
    border-radius: 8px;
    cursor: pointer;
    user-select: none;
    transition: opacity 0.3s;
}

.captcha-image:hover {
    opacity: 0.8;
}

.login-btn {
    width: 100%;
    padding: 12px;
    background: #4A90E2;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.3s;
    margin-top: 10px;
}

.login-btn:hover {
    background: #357ABD;
}

/* 黄色不规则形状 - 右上角 */
.login-container::before {
    content: '';
    position: fixed;
    top: -80px;
    right: -80px;
    width: 250px;
    height: 250px;
    background: #FFD700;
    border-radius: 45% 55% 50% 50% / 60% 40% 60% 40%;
    transform: rotate(25deg);
    z-index: 0;
    opacity: 0.9;
}

/* 红色三角形 - 左下角 */
.login-container::after {
    content: '';
    position: fixed;
    bottom: -60px;
    left: -60px;
    width: 0;
    height: 0;
    border-left: 120px solid transparent;
    border-right: 120px solid transparent;
    border-bottom: 180px solid #FF4444;
    border-radius: 15px;
    z-index: 0;
    opacity: 0.9;
    transform: rotate(-15deg);
}

/* 浅绿色不规则形状 - 右下角 */
body::before {
    content: '';
    position: fixed;
    bottom: -80px;
    right: -80px;
    width: 300px;
    height: 300px;
    background: #90EE90;
    border-radius: 50% 40% 60% 50% / 60% 50% 50% 40%;
    transform: rotate(-25deg);
    z-index: 0;
    opacity: 0.9;
}

/* 响应式设计 - 移动端适配 */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    .login-container {
        max-width: 100%;
        padding: 15px;
    }
    
    .form-group {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .form-group label {
        min-width: auto;
        text-align: left;
        width: 100%;
    }
    
    .form-group input {
        width: 100%;
    }
    
    .captcha-group {
        width: 100%;
        flex-direction: column;
        gap: 10px;
    }
    
    .captcha-image {
        width: 100%;
        max-width: 200px;
        height: 50px;
    }
    
    .login-btn {
        width: 100%;
        padding: 14px;
        font-size: 16px;
    }
}

/* 超小屏幕适配 */
@media (max-width: 480px) {
    .login-container {
        padding: 10px;
    }
    
    .form-group {
        margin-bottom: 15px;
    }
    
    .captcha-image {
        height: 45px;
    }
}