/* ========== 基础变量定义（来自 Bootstrap） ========== */
:root {
  --bs-blue: #0f2501;
  --bs-indigo: #6610f2;
  --bs-purple: #6f42c1;
  --bs-pink: #d63384;
  --bs-red: #dc3545;
  --bs-orange: #fd7e14;
  --bs-yellow: #ffc107;
  --bs-green: #198754;
  --bs-cyan: #0dcaf0;
  --bs-black: #1a1919;
  --bs-white: #fff;
  --bs-gray: #6c757d;
  --bs-gray-dark: #343a40;

  --bs-font-sans-serif: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

  --bs-body-font-family: var(--bs-font-sans-serif);
  --bs-body-font-size: 1rem;
  --bs-body-font-weight: 400;
  --bs-body-line-height: 1.5;
  --bs-body-color: #212529;
  --bs-body-bg: #fff;
  --bs-heading-color: inherit;
  --bs-link-color: #0f2501;
}

/* ========== 全局基础样式 ========== */
*,
::before,
::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--bs-body-font-family);
  font-size: var(--bs-body-font-size);
  font-weight: var(--bs-body-font-weight);
  line-height: var(--bs-body-line-height);
  color: white;
  background-color: black;
}

/* ========== 标题样式 ========== */
h1, h2, h3, h4 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-weight: 500;
  line-height: 1.2;
  color: var(--bs-heading-color);
}
h1 {
  font-size: calc(1.375rem + 1.5vw);
}
h2 {
  font-size: calc(1.325rem + 0.9vw);
}
h3 {
  font-size: calc(1.3rem + 0.6vw);
}
h4 {
  font-size: calc(1.275rem + 0.3vw);
}
@media (min-width: 1200px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 2rem; }
  h3 { font-size: 1.75rem; }
  h4 { font-size: 1.5rem; }
}

/* ========== 容器与布局 ========== */
.container {
  width: 100%;
  padding-left: 0.75rem;
  padding-right: 0.75rem;
  margin-left: auto;
  margin-right: auto;
}
@media (min-width: 768px) {
  .container { max-width: 960px; }
}
.row {
  display: flex;
  flex-wrap: wrap;
  margin-left: -0.75rem;
  margin-right: -0.75rem;
}
.row > * {
  padding-left: 0.75rem;
  padding-right: 0.75rem;
  width: 100%;
}
.col-12 {
  flex: 0 0 auto;
  width: 100%;
}
@media (min-width: 992px) {
  .col-lg-6 {
    width: 50%;
  }
}

/* ========== 通用工具类 ========== */
.text-center {
  text-align: center !important;
}
.text-white {
  color: #fff !important;
}
.text-decoration-none {
  text-decoration: none !important;
}
.rounded-2 {
  border-radius: 0.375rem !important;
}
.rounded-5 {
  border-radius: 2rem !important;
}
.d-flex {
  display: flex !important;
}
.justify-content-between {
  justify-content: space-between !important;
}
.justify-content-center {
  justify-content: center !important;
}
.align-items-center {
  align-items: center !important;
}
.me-2 { margin-right: 0.5rem !important; }
.me-3 { margin-right: 1rem !important; }
.ms-3 { margin-left: 1rem !important; }
.my-2 { margin-top: 0.5rem !important; margin-bottom: 0.5rem !important; }
.py-2 { padding-top: 0.5rem !important; padding-bottom: 0.5rem !important; }
.py-5 { padding-top: 3rem !important; padding-bottom: 3rem !important; }
.w-100 { width: 100% !important; }
.bg-primary {
  background-color: rgba(13, 110, 253, 1) !important;
}

/* ========== 按钮样式 ========== */
.btn {
  padding: 10px 20px;
  font-size: 16px;
  border-radius: 5px;
  text-decoration: none;
  display: inline-block;
  border: none;
  color: #fff;
}
.btn-primary {
  background-color: #0f2501;
}
.btn-primary:hover {
  background-color: #0a58ca;
}
.btn-success {
  background-color: #198754;
}
.btn-success:hover {
  background-color: #146c43;
}
.btn-lg {
  font-size: 1.25rem;
  padding: 0.5rem 1rem;
  border-radius: 0.5rem;
}

/* ========== 图片样式 ========== */
.img-fluid {
  max-width: 100%;
  height: auto;
}

/* ========== 富媒体缩放动画 ========== */
.media-zoom {
  transition: transform 0.4s ease, box-shadow 0.4s ease;
  cursor: pointer;
}
.media-zoom:hover {
  transform: scale(1.08);
  box-shadow: 0 8px 20px rgba(255, 255, 255, 0.2);
}