/* Bootstrap 4.6.2 简化版 - 核心样式 */

/* 容器和网格系统 */
.container {
    width: 100%;
    padding-right: 15px;
    padding-left: 15px;
    margin-right: auto;
    margin-left: auto;
}

@media (min-width: 576px) {
    .container { max-width: 540px; }
}

@media (min-width: 768px) {
    .container { max-width: 720px; }
}

@media (min-width: 992px) {
    .container { max-width: 960px; }
}

@media (min-width: 1200px) {
    .container { max-width: 1140px; }
}

.row {
    display: flex;
    flex-wrap: wrap;
    margin-right: -15px;
    margin-left: -15px;
}

.col, .col-1, .col-2, .col-3, .col-4, .col-5, .col-6, .col-7, .col-8, .col-9, .col-10, .col-11, .col-12,
.col-sm, .col-sm-1, .col-sm-2, .col-sm-3, .col-sm-4, .col-sm-5, .col-sm-6, .col-sm-7, .col-sm-8, .col-sm-9, .col-sm-10, .col-sm-11, .col-sm-12,
.col-md, .col-md-1, .col-md-2, .col-md-3, .col-md-4, .col-md-5, .col-md-6, .col-md-7, .col-md-8, .col-md-9, .col-md-10, .col-md-11, .col-md-12,
.col-lg, .col-lg-1, .col-lg-2, .col-lg-3, .col-lg-4, .col-lg-5, .col-lg-6, .col-lg-7, .col-lg-8, .col-lg-9, .col-lg-10, .col-lg-11, .col-lg-12,
.col-xl, .col-xl-1, .col-xl-2, .col-xl-3, .col-xl-4, .col-xl-5, .col-xl-6, .col-xl-7, .col-xl-8, .col-xl-9, .col-xl-10, .col-xl-11, .col-xl-12 {
    position: relative;
    width: 100%;
    padding-right: 15px;
    padding-left: 15px;
}

.col { flex-basis: 0; flex-grow: 1; max-width: 100%; }
.col-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
.col-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
.col-3 { flex: 0 0 25%; max-width: 25%; }
.col-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
.col-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
.col-6 { flex: 0 0 50%; max-width: 50%; }
.col-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
.col-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
.col-9 { flex: 0 0 75%; max-width: 75%; }
.col-10 { flex: 0 0 83.333333%; max-width: 83.333333%; }
.col-11 { flex: 0 0 91.666667%; max-width: 91.666667%; }
.col-12 { flex: 0 0 100%; max-width: 100%; }

@media (min-width: 768px) {
    .col-md { flex-basis: 0; flex-grow: 1; max-width: 100%; }
    .col-md-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
    .col-md-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
    .col-md-3 { flex: 0 0 25%; max-width: 25%; }
    .col-md-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
    .col-md-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
    .col-md-6 { flex: 0 0 50%; max-width: 50%; }
    .col-md-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
    .col-md-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
    .col-md-9 { flex: 0 0 75%; max-width: 75%; }
    .col-md-10 { flex: 0 0 83.333333%; max-width: 83.333333%; }
    .col-md-11 { flex: 0 0 91.666667%; max-width: 91.666667%; }
    .col-md-12 { flex: 0 0 100%; max-width: 100%; }
}

@media (min-width: 992px) {
    .col-lg { flex-basis: 0; flex-grow: 1; max-width: 100%; }
    .col-lg-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
    .col-lg-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
    .col-lg-3 { flex: 0 0 25%; max-width: 25%; }
    .col-lg-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
    .col-lg-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
    .col-lg-6 { flex: 0 0 50%; max-width: 50%; }
    .col-lg-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
    .col-lg-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
    .col-lg-9 { flex: 0 0 75%; max-width: 75%; }
    .col-lg-10 { flex: 0 0 83.333333%; max-width: 83.333333%; }
    .col-lg-11 { flex: 0 0 91.666667%; max-width: 91.666667%; }
    .col-lg-12 { flex: 0 0 100%; max-width: 100%; }
}

/* 对齐 */
.align-items-center { align-items: center !important; }
.justify-content-center { justify-content: center !important; }
.text-center { text-align: center !important; }
.text-right { text-align: right !important; }
.text-left { text-align: left !important; }

/* 间距 */
.mb-0 { margin-bottom: 0 !important; }
.mb-1 { margin-bottom: 0.25rem !important; }
.mb-2 { margin-bottom: 0.5rem !important; }
.mb-3 { margin-bottom: 1rem !important; }
.mb-4 { margin-bottom: 1.5rem !important; }
.mb-5 { margin-bottom: 3rem !important; }

.mt-0 { margin-top: 0 !important; }
.mt-1 { margin-top: 0.25rem !important; }
.mt-2 { margin-top: 0.5rem !important; }
.mt-3 { margin-top: 1rem !important; }
.mt-4 { margin-top: 1.5rem !important; }
.mt-5 { margin-top: 3rem !important; }

.py-0 { padding-top: 0 !important; padding-bottom: 0 !important; }
.py-1 { padding-top: 0.25rem !important; padding-bottom: 0.25rem !important; }
.py-2 { padding-top: 0.5rem !important; padding-bottom: 0.5rem !important; }
.py-3 { padding-top: 1rem !important; padding-bottom: 1rem !important; }
.py-4 { padding-top: 1.5rem !important; padding-bottom: 1.5rem !important; }
.py-5 { padding-top: 3rem !important; padding-bottom: 3rem !important; }

.ml-auto { margin-left: auto !important; }
.mr-auto { margin-right: auto !important; }
.ml-3 { margin-left: 1rem !important; }

/* 按钮 */
.btn {
    display: inline-block;
    font-weight: 400;
    color: #212529;
    text-align: center;
    vertical-align: middle;
    cursor: pointer;
    background-color: transparent;
    border: 1px solid transparent;
    padding: 0.375rem 0.75rem;
    font-size: 1rem;
    line-height: 1.5;
    border-radius: 0.25rem;
    transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
    text-decoration: none;
}

.btn:hover {
    color: #212529;
    text-decoration: none;
}

.btn-primary {
    color: #fff;
    background-color: #007bff;
    border-color: #007bff;
}

.btn-primary:hover {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
}

.btn-outline-primary {
    color: #007bff;
    border-color: #007bff;
}

.btn-outline-primary:hover {
    color: #fff;
    background-color: #007bff;
    border-color: #007bff;
}

.btn-lg {
    padding: 0.5rem 1rem;
    font-size: 1.25rem;
    line-height: 1.5;
    border-radius: 0.3rem;
}

/* 导航栏 */
.navbar {
    position: relative;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    padding: 0.5rem 1rem;
}

.navbar-brand {
    display: inline-block;
    padding-top: 0.3125rem;
    padding-bottom: 0.3125rem;
    margin-right: 1rem;
    font-size: 1.25rem;
    line-height: inherit;
    white-space: nowrap;
    text-decoration: none;
}

.navbar-nav {
    display: flex;
    flex-direction: column;
    padding-left: 0;
    margin-bottom: 0;
    list-style: none;
}

.navbar-nav .nav-link {
    padding-right: 0;
    padding-left: 0;
    color: rgba(0,0,0,.5);
    text-decoration: none;
}

.navbar-nav .nav-link:hover {
    color: rgba(0,0,0,.7);
}

.navbar-expand-lg .navbar-nav {
    flex-direction: row;
}

.navbar-expand-lg .navbar-nav .nav-link {
    padding-right: 0.5rem;
    padding-left: 0.5rem;
}

.navbar-toggler {
    padding: 0.25rem 0.75rem;
    font-size: 1.25rem;
    line-height: 1;
    background-color: transparent;
    border: 1px solid transparent;
    border-radius: 0.25rem;
}

.collapse:not(.show) {
    display: none;
}

@media (min-width: 992px) {
    .navbar-expand-lg .collapse {
        display: flex !important;
        flex-basis: auto;
    }
    .navbar-expand-lg .navbar-toggler {
        display: none;
    }
}

/* 卡片 */
.card {
    position: relative;
    display: flex;
    flex-direction: column;
    min-width: 0;
    word-wrap: break-word;
    background-color: #fff;
    background-clip: border-box;
    border: 1px solid rgba(0,0,0,.125);
    border-radius: 0.25rem;
}

.card-body {
    flex: 1 1 auto;
    min-height: 1px;
    padding: 1.25rem;
}

.card-title {
    margin-bottom: 0.75rem;
}

.card-text:last-child {
    margin-bottom: 0;
}

.card-img-top {
    width: 100%;
    border-top-left-radius: calc(0.25rem - 1px);
    border-top-right-radius: calc(0.25rem - 1px);
}

/* 高度 */
.h-100 { height: 100% !important; }
.min-vh-100 { min-height: 100vh !important; }

/* 背景 */
.bg-light { background-color: #f8f9fa !important; }

/* 下拉菜单 */
.dropdown {
    position: relative;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    z-index: 1000;
    display: none;
    float: left;
    min-width: 10rem;
    padding: 0.5rem 0;
    margin: 0.125rem 0 0;
    font-size: 1rem;
    color: #212529;
    text-align: left;
    list-style: none;
    background-color: #fff;
    background-clip: padding-box;
    border: 1px solid rgba(0,0,0,.15);
    border-radius: 0.25rem;
}

.dropdown-item {
    display: block;
    width: 100%;
    padding: 0.25rem 1.5rem;
    clear: both;
    font-weight: 400;
    color: #212529;
    text-align: inherit;
    white-space: nowrap;
    background-color: transparent;
    border: 0;
    text-decoration: none;
}

.dropdown-item:hover {
    color: #16181b;
    background-color: #f8f9fa;
    text-decoration: none;
}