* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Microsoft Yahei", sans-serif;
}

body {
    background-color: #f5f7fa;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.login-box {
    background: #fff;
    width: 360px;
    padding: 35px 30px;
    border-radius: 10px;
    box-shadow: 0 2px 15px rgba(0,0,0,0.1);
}

.login-box h2 {
    text-align: center;
    color: #333;
    margin-bottom: 25px;
}

.tip-message {
    padding: 10px;
    background: #ffebee;
    color: #c62828;
    border-radius: 6px;
    margin-bottom: 20px;
    text-align: center;
}

.input-item {
    margin-bottom: 18px;
}

.input-item label {
    display: block;
    margin-bottom: 6px;
    color: #555;
    font-size:14px;
}

/* 账号、密码输入框 */
.input-item input {
    width: 100%;
    height: 42px;
    padding: 0 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 15px;
    outline: none;
    transition: border-color 0.2s ease;
}

.input-item input:focus {
    border-color: #2196F3;
}

/* 验证码行容器 */
.captcha-wrap {
    display: flex;
    gap: 12px;
    align-items: stretch;
    margin: 18px 0;
}

/* 验证码图片，和输入框等高42px，圆角和表单统一6px */
#captchaImg {
    height: 42px;
    border: 1px solid #ddd;
    border-radius: 6px;
    flex-shrink: 0;
    object-fit: cover;
    cursor: pointer;
    transition: filter 0.2s;
}
#captchaImg:hover{
    filter: brightness(0.95);
}

/* 验证码输入框：继承表单输入框全部样式，flex占剩余宽度 */
.captcha-wrap input {
    flex: 1;
    height:42px;
    padding:0 12px;
    border:1px solid #ddd;
    border-radius:6px;
    font-size:15px;
    outline:none;
    transition: border-color 0.2s ease;
}
.captcha-wrap input:focus{
    border-color:#2196F3;
}
.captcha-wrap input::placeholder {
    color:#aaa;
}

/* 登录按钮 */
.submit-btn {
    width: 100%;
    height: 44px;
    background: #2196F3;
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    cursor: pointer;
    transition: background 0.2s;
}

.submit-btn:hover:not(:disabled) {
    background: #1976D2;
}

.submit-btn:disabled {
    background:#81baf0;
    cursor:not-allowed;
}

.msg-tip {
    padding: 8px;
    border-radius:6px;
    margin-bottom:16px;
    text-align:center;
}