:root {
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    --card-bg: rgba(15, 23, 42, 0.7);
    --text-main: #ffffff;
    --text-muted: #cbd5e1;
    --accent-color: #38bdf8;
    /* Sky Blue */
    --accent-hover: #7dd3fc;
    --nav-bg: transparent;
    --border-radius: 16px;
    --shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
    --glass-border: rgba(255, 255, 255, 0.15);
}

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

body {
    background: url('images/101_1920x1200.jpg') no-repeat center center fixed;
    background-size: cover;
    color: var(--text-main);
    font-family: "Microsoft YaHei", "Heiti SC", sans-serif;
    min-height: 100vh;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 2px;
}

::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.1);
}

::-webkit-scrollbar-thumb {
    background: var(--accent-color);
    border-radius: 4px;
}

/* Navigation - Top Bar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 70px;
    backdrop-filter: blur(20px) saturate(180%);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    padding: 0 40px;
}

.nav-menu {
    display: flex;
    justify-content: center;
    height: 100%;
}

.nav-auth {
    position: absolute;
    right: 40px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    /* 确保内容在容器内水平也居中（如果容器有宽度） */
}

.nav-item {
    padding: 0 25px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    /* 确保文字在 nav-item 内居中 */
    color: var(--text-muted);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.5);
}

.nav-item:hover {
    color: #fff;
}

.nav-item.active {
    color: var(--accent-color);
    font-weight: bold;
}

.nav-item::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--accent-color);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.nav-item.active::after,
.nav-item:hover::after {
    width: 60%;
}

/* Main Layout */
.main-wrapper {
    background: rgba(0, 0, 0, 0.2);
    padding-top: 20px;
    /* Space for fixed nav */
    padding-bottom: 40px;
    min-height: 100vh;
    display: flex;
    justify-content: center;
}

/* Cards & Panels */
.panel {
    background: transparent;
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--shadow);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    animation: slideUp 0.5s ease-out;
    width: 100%;
    max-width: 1000px;
}

/* Typography */
h1,
h2,
h3 {
    color: #fff;
    margin-bottom: 25px;
    font-weight: 600;
    text-align: center;
    position: relative;
    padding-bottom: 15px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

h1::after,
h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 2px;
}

/* Forms */
label {
    display: block;
    margin-bottom: 10px;
    color: #ffffff;
    font-size: 1em;
    font-weight: 600;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

input[type="text"],
input[type="password"],
input[type="number"] {
    width: 100%;
    padding: 14px 16px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 10px;
    color: #fff;
    font-size: 1em;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    outline: none;
    margin-bottom: 20px;
}

input:focus {
    border-color: var(--accent-color);
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
}

.password-wrapper {
    position: relative;
    width: 100%;
    margin-bottom: 20px;
}

.password-wrapper input {
    padding-right: 45px !important;
    margin-bottom: 0 !important;
}

.toggle-password {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    cursor: pointer;
    color: var(--text-muted);
    width: 32px;
    height: 32px;
    padding: 6px;
    user-select: none;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0.6;
}

.toggle-password svg {
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.toggle-password:hover {
    color: var(--accent-color);
    opacity: 1;
}

.toggle-password:hover {
    color: var(--accent-color);
}

/* Buttons */
.btn {
    background: var(--accent-color);
    color: #fff;
    border: none;
    padding: 14px 30px;
    border-radius: 30px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    box-shadow: 0 4px 15px rgba(233, 69, 96, 0.3);
    display: inline-block;
    text-align: center;
}

.btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(56, 189, 248, 0.4);
}

.btn:active {
    transform: translateY(0);
}

/* Tabs */
.tabs {
    display: flex;
    justify-content: center;
    margin-bottom: 35px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    padding: 5px;
    border-radius: 30px;
    display: inline-flex;
    position: relative;
    left: 50%;
    transform: translateX(-50%);
}

.tab-button {
    padding: 10px 25px;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
}

.tab-button.active {
    background: var(--accent-color);
    color: #fff;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

.tab-content {
    display: none;
    animation: fadeIn 0.4s ease;
}

.tab-content.active {
    display: block;
}

/* Alerts */
.alert {
    position: fixed;
    top: 90px;
    right: 20px;
    padding: 15px 25px;
    border-radius: 8px;
    color: #fff;
    font-weight: 500;
    z-index: 2000;
    animation: slideInRight 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    display: flex;
    align-items: center;
}

.alert.success {
    background: linear-gradient(to right, #11998e, #38ef7d);
}

.alert.error {
    background: linear-gradient(to right, #cb2d3e, #ef473a);
}

/* Animations */
@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

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

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }

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

/* Responsive */
@media (max-width: 768px) {
    .navbar {
        height: auto;
        padding: 10px 0;
    }

    .nav-item {
        padding: 10px 15px;
        font-size: 14px;
    }

    .panel {
        padding: 25px;
    }
}