:root {
    --primary-gradient: linear-gradient(135deg, #00c6fb 0%, #005bea 100%);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.8);
    --input-bg: rgba(255, 255, 255, 0.1);
    --input-border: rgba(255, 255, 255, 0.3);
    --input-focus: #00c6fb;
    --glass-bg: rgba(255, 255, 255, 0.15);
    --glass-border: rgba(255, 255, 255, 0.2);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Noto Sans SC', 'Roboto', sans-serif;
}

body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: url("https://images.unsplash.com/photo-1464822759023-fed622ff2c3b?ixlib=rb-4.0.3&auto=format&fit=crop&w=2000&q=80");
    background-size: cover;
    background-position: center;
    position: relative;
}

body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
    /* Darken background for contrast */
    z-index: 0;
}

.login-container {
    width: 100%;
    max-width: 580px;
    /* Wider container */
    padding: 20px;
    z-index: 1;
    animation: fadeInUp 1s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.login-header {
    text-align: center;
    margin-bottom: 40px;
    /* More spacing */
}

.main-title {
    font-size: 3.5rem;
    /* Larger title */
    font-weight: 700;
    color: #fff;
    text-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
    margin-bottom: 15px;
    letter-spacing: 4px;
    /* More letter spacing */
}

.subtitle {
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.9);
    letter-spacing: 2px;
}

/* Glass Card */
.login-card {
    background: var(--glass-bg);
    backdrop-filter: blur(25px);
    /* Stronger blur */
    -webkit-backdrop-filter: blur(25px);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    border-radius: 24px;
    padding: 60px 50px;
    /* More padding */
    color: #fff;
    transition: transform 0.3s ease;
}

.login-card:hover {
    transform: translateY(-5px);
}

.card-header {
    text-align: center;
    margin-bottom: 40px;
}

.card-header h2 {
    font-size: 1.8rem;
    font-weight: 600;
    letter-spacing: 3px;
    margin-bottom: 15px;
}

.underline {
    width: 60px;
    height: 4px;
    background: #00c6fb;
    margin: 0 auto;
    border-radius: 2px;
}

/* Form Groups */
.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    font-size: 0.9rem;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-weight: 500;
}

.input-wrapper {
    position: relative;
}

.input-wrapper i {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    color: rgba(255, 255, 255, 0.6);
    transition: color 0.3s;
}

.input-icon {
    left: 15px;
    font-size: 1.2rem;
}

.toggle-password {
    right: 15px;
    cursor: pointer;
    font-size: 1.2rem;
}

.toggle-password:hover {
    color: #fff;
}

.input-wrapper input {
    width: 100%;
    padding: 12px 45px;
    /* Space for icons */
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 30px;
    /* Pillow shape for modern look */
    color: #fff;
    font-size: 1rem;
    outline: none;
    transition: all 0.3s;
}

.input-wrapper input::placeholder {
    color: rgba(255, 255, 255, 0.4);
}

.input-wrapper input:focus {
    background: rgba(255, 255, 255, 0.2);
    border-color: var(--input-focus);
    box-shadow: 0 0 15px rgba(0, 198, 251, 0.3);
}

.input-wrapper input:focus+i {
    color: #fff;
}

/* Button */
.login-btn {
    width: 100%;
    padding: 12px;
    background: var(--primary-gradient);
    border: none;
    border-radius: 30px;
    color: #fff;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 5px 15px rgba(0, 200, 251, 0.4);
    transition: all 0.3s;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.login-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 200, 251, 0.6);
}

.login-btn:active {
    transform: scale(0.98);
}

/* Footer & Alerts */
.footer {
    text-align: center;
    margin-top: 30px;
    font-size: 0.8rem;
}

.footer a {
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    margin: 0 10px;
}

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

.alert {
    padding: 10px 15px;
    border-radius: 10px;
    margin-bottom: 20px;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 10px;
    backdrop-filter: blur(5px);
}

.alert-error {
    background: rgba(255, 82, 82, 0.2);
    border: 1px solid rgba(255, 82, 82, 0.4);
    color: #ff8a80;
}

.alert-success {
    background: rgba(105, 240, 174, 0.2);
    border: 1px solid rgba(105, 240, 174, 0.4);
    color: #69f0ae;
}

/* ----------------------------------
   Mobile Responsiveness (手机端自适应)
   --------------------------------- */
@media (max-width: 576px) {
    .login-container {
        padding: 15px;
    }

    .login-header {
        margin-bottom: 25px;
    }

    .main-title {
        font-size: 2.2rem;
        letter-spacing: 2px;
    }

    .subtitle {
        font-size: 0.9rem;
        letter-spacing: 1px;
    }

    .login-card {
        padding: 40px 25px;
        border-radius: 18px;
    }

    .card-header {
        margin-bottom: 25px;
    }

    .card-header h2 {
        font-size: 1.5rem;
    }

    .form-group {
        margin-bottom: 20px;
    }

    .input-wrapper input {
        padding: 10px 40px;
        font-size: 0.95rem;
    }
}

/* 首页悬浮二维码导航样式 */
.floating-nav {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    gap: 15px;
    z-index: 999;
}

.float-item {
    position: relative;
}

.float-item .icon-btn {
    width: 60px;
    height: 60px;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: #fff;
    cursor: pointer;
    transition: all 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
    /* Add a slight bounce effect */
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.float-item .icon-btn i {
    font-size: 24px;
    margin-bottom: 4px;
    color: #00c6fb;
}

.float-item .icon-btn span {
    font-size: 12px;
    font-weight: 500;
}

.float-item:hover .icon-btn {
    background: rgba(255, 255, 255, 0.25);
    border-color: #00c6fb;
    transform: translateX(-5px);
}

.qr-popup {
    position: absolute;
    right: 80px;
    top: 50%;
    transform: translateY(-50%) translateX(30px) scale(0.9);
    background: #fff;
    padding: 15px;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    opacity: 0;
    visibility: hidden;
    transition: all 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
    width: 160px;
    text-align: center;
    pointer-events: none;
}

/* popup tail arrow */
.qr-popup::after {
    content: '';
    position: absolute;
    right: -8px;
    top: 50%;
    transform: translateY(-50%);
    border-width: 8px 0 8px 8px;
    border-style: solid;
    border-color: transparent transparent transparent #fff;
}

.float-item:hover .qr-popup {
    opacity: 1;
    visibility: visible;
    transform: translateY(-50%) translateX(0) scale(1.0);
}

.qr-title {
    font-size: 14px;
    color: #333;
    font-weight: bold;
    margin-bottom: 10px;
}

.qr-popup img {
    width: 130px;
    height: 130px;
    object-fit: cover;
    /* Change cover instead of contain to avoid weird ratios */
    border-radius: 8px;
    border: 1px solid #eee;
}

@media (max-width: 768px) {
    .floating-nav {
        display: none;
        /* 小屏幕隐藏二维码导航，节省空间 */
    }
}