/* 全局样式 */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
}

/* 背景图 - 更新为bg.png */
.hero-section {
    background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.7)), url('../img/bg.png') center/cover no-repeat fixed;
    min-height: 100vh;
    position: relative;
}

/* 导航栏初始透明样式 */
#navbar {
    background-color: transparent;
    border-bottom: 1px solid transparent;
}

/* 导航栏滚动后样式 */
#navbar.scrolled {
    background-color: rgba(17, 24, 39, 0.8);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid rgba(55, 65, 81, 0.5);
}

/* 导航链接 */
.nav-link {
    color: #d1d5db;
    text-decoration: none;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover, .nav-link.active {
    color: #4ade80;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: #4ade80;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: #22c55e;
    color: white;
}

.btn-primary:hover {
    background-color: #16a34a;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(34, 197, 94, 0.3);
}

.btn-secondary {
    background-color: rgba(75, 85, 99, 0.8);
    color: white;
    backdrop-filter: blur(4px);
}

.btn-secondary:hover {
    background-color: rgba(55, 65, 81, 0.9);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(75, 85, 99, 0.3);
}

/* 卡片样式 */
.card {
    background-color: #1f2937;
    border-radius: 0.75rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

/* 捐款者卡片 */
.donor-card {
    background-color: #1f2937;
    border-radius: 0.75rem;
    transition: all 0.3s ease;
}

.donor-card:hover {
    background-color: #374151;
    transform: translateX(5px);
}

/* 画廊项目 */
.gallery-item {
    position: relative;
    overflow: hidden;
    border-radius: 0.75rem;
    cursor: pointer;
}

.gallery-item img {
    transition: transform 0.5s ease;
}

.gallery-item:hover img {
    transform: scale(1.1);
}

.gallery-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(transparent, rgba(0, 0, 0, 0.8));
    padding: 1rem;
    transform: translateY(100%);
    transition: transform 0.3s ease;
}

.gallery-item:hover .gallery-overlay {
    transform: translateY(0);
}

/* 文本阴影 */
.text-shadow {
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.7);
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #1f2937;
}

::-webkit-scrollbar-thumb {
    background: #4b5563;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #6b7280;
}

/* 动画 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeIn 0.5s ease forwards;
}

/* 英雄页渐入动画 */
.animate-fade-in {
    animation: fadeIn 0.8s ease forwards;
}

.animate-fade-in-delay-1 {
    animation: fadeIn 0.8s ease 0.2s forwards;
    opacity: 0;
}

.animate-fade-in-delay-2 {
    animation: fadeIn 0.8s ease 0.4s forwards;
    opacity: 0;
}

.animate-fade-in-delay-3 {
    animation: fadeIn 0.8s ease 0.6s forwards;
    opacity: 0;
}

.animate-fade-in-delay-4 {
    animation: fadeIn 0.8s ease 0.8s forwards;
    opacity: 0;
}

/* 弹跳动画 */
@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0) translateX(-50%); }
    40% { transform: translateY(-10px) translateX(-50%); }
    60% { transform: translateY(-5px) translateX(-50%); }
}

.animate-bounce {
    animation: bounce 2s infinite;
}