:root {
    --primary-color: #FF6B6B;
    --secondary-color: #4ECDC4;
    --text-color: #2D3436;
    --light-text: #636E72;
    --bg-color: #F7F9FC;
    --white: #FFFFFF;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    /* scroll-padding-top removed in favor of scroll-margin-top on sections */
}

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--primary-color);
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white) !important;
    padding: 0.5rem 1.5rem;
    border-radius: 25px;
    transition: var(--transition);
}

.btn-primary:hover {
    background-color: #FF5252;
    transform: translateY(-2px);
}

.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
}

/* Sections Scroll Margin for Sticky Navbar */
section {
    scroll-margin-top: 120px;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, #FFF5F5 0%, #FFFFFF 100%);
    min-height: 80vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.hero-text {
    flex: 1.4;
}

.hero-text h1 {
    font-size: 3.5rem;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

.hero-text p {
    font-size: 1rem;
    color: var(--light-text);
    margin-bottom: 2rem;
    max-width: 500px;
}

.download-buttons {
    display: flex;
    flex-direction: column; /* 改为纵向排列，配合 HTML 中的行内 flex 布局实现两行 */
    gap: 1rem;
    margin-bottom: 1rem;
    align-items: flex-start; /* 确保子元素左对齐 */
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--text-color);
    color: var(--white);
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    font-weight: bold;
    transition: var(--transition);
    position: relative; /* 为 Tooltip 定位 */
}

/* Tooltip 样式 */
.btn-download::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 120%; /* 显示在按钮上方 */
    left: 50%;
    transform: translateX(-50%);
    background-color: #333;
    color: #fff;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    font-size: 0.8rem;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
    pointer-events: none;
    z-index: 100;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

/* 小三角 */
.btn-download::before {
    content: '';
    position: absolute;
    bottom: 110%; /* 紧贴 Tooltip 下方 */
    left: 50%;
    transform: translateX(-50%);
    border-width: 5px;
    border-style: solid;
    border-color: #333 transparent transparent transparent;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
    pointer-events: none;
    z-index: 100;
}

/* 针对 tooltip-bottom 类的样式覆盖 */
.btn-download.tooltip-bottom::after {
    bottom: auto;
    top: 120%; /* 显示在按钮下方 */
}

.btn-download.tooltip-bottom::before {
    bottom: auto;
    top: 110%; /* 紧贴 Tooltip 上方 */
    border-color: transparent transparent #333 transparent; /* 箭头向上 */
}

.btn-download:hover::after,
.btn-download:hover::before {
    opacity: 1;
    visibility: visible;
}

.btn-download:hover {
    background-color: #000;
    transform: translateY(-2px);
}

.btn-download img {
    width: 1.2rem;
    height: 1.2rem;
    object-fit: contain;
    filter: brightness(0) invert(1); /* 确保图标为白色，适配深色背景 */
}

.hero-note {
    font-size: 0.9rem;
    color: var(--light-text);
    font-style: italic;
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

/* Phone Mockup & Carousel */
.phone-mockup {
    width: 300px;
    aspect-ratio: 1290 / 2796;
    background-color: #fff;
    border-radius: 30px;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
    box-shadow: 0 20px 50px rgba(0,0,0,0.2);
    transform: rotate(-5deg);
    transition: var(--transition);
}

.phone-mockup:hover {
    transform: rotate(0) scale(1.02);
}

/* 移除刘海模拟，改为更现代的全面屏风格 */
.phone-mockup::before {
    display: none; 
}

.carousel-container {
    width: 100%;
    height: 100%;
    position: relative;
    background-color: #fff;
}

.carousel-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    transition: opacity 0.8s ease-in-out;
}

.carousel-container img.active {
    opacity: 1;
}

/* Features Section */
.features {
    padding: 5rem 0;
    background-color: var(--white);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--text-color);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-color);
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow);
}

.feature-card .icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.feature-card h3 {
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.feature-card p {
    color: var(--light-text);
}

/* Support & Business Split Section */
.support-business {
    padding: 0 0 5rem 0;
    background-color: #F8F9FA;
}

.split-layout {
    display: flex;
    gap: 4rem;
    align-items: stretch;
}

.split-col {
    flex: 1;
    background: var(--white);
    padding: 2.5rem;
    border-radius: 20px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    /* 确保内部元素可以撑开布局 */
    display: flex;
    flex-direction: column;
}

.split-col h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.split-col .desc {
    color: var(--light-text);
    margin-bottom: 2rem;
    line-height: 1.6;
}

/* Donate Column Styles */
.donate-col {
    justify-content: center;
    text-align: center;
}

.donate-col h2 i {
    color: var(--primary-color);
    margin-right: 0.4rem;
    font-size: 1.5rem;
    vertical-align: middle;
}

.donate-col .desc {
    text-align: left;
}

.donation-methods {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.method {
    text-align: center;
}

.method img {
    width: 160px;
    height: 160px;
    border-radius: 10px;
    margin-bottom: 0.5rem;
    border: 1px solid #eee;
}

.other-support {
    background: linear-gradient(135deg, #fff8f5 0%, #fff0eb 100%);
    padding: 1.75rem 1.5rem;
    border-radius: 14px;
    border: 1px solid rgba(255, 107, 107, 0.1);
    text-align: left;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.other-support h3 {
    font-size: 1.05rem;
    color: var(--text-color);
    margin-bottom: 1rem;
    padding-bottom: 0.6rem;
    border-bottom: 1px dashed rgba(255, 107, 107, 0.25);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.other-support h3::before {
    content: "";
    display: inline-block;
    width: 4px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 2px;
}

.other-support ul {
    margin: 0;
    padding: 0;
    list-style: none;
}

.other-support li {
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 0.4rem;
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    color: var(--text-color);
    transition: transform 0.2s ease;
}

.other-support li:last-child {
    margin-bottom: 0;
}

.other-support li:hover {
    transform: translateX(4px);
}

.other-support li i {
    color: var(--primary-color);
    margin-top: 0.35rem;
    flex-shrink: 0;
    width: 16px;
    text-align: center;
}

.highlight {
    color: var(--primary-color);
    font-weight: 600;
}

.qr-customer-service {
    text-align: center;
    margin: 1rem 0 1.5rem;
    padding: 1rem;
    background-color: #fff;
    border-radius: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.qr-customer-service img {
    width: 150px;
    height: 150px;
    border-radius: 8px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.08);
}

.qr-customer-service p {
    font-size: 0.9rem;
    color: var(--light-text);
    margin: 0;
}

/* Business Column Styles */
.business-col .contact-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    flex: 1;
    justify-content: center; /* 让联系方式在垂直方向居中，看起来更饱满 */
}

.contact-row {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 1rem;
    border-radius: 10px;
    transition: var(--transition);
    background-color: #fff;
    border: 1px solid #eee;
}

.contact-row:hover {
    border-color: var(--primary-color);
    transform: translateX(5px);
}

.icon-box {
    width: 50px;
    height: 50px;
    background-color: #FFF0F0;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--primary-color);
}

.info-box h4 {
    font-size: 0.9rem;
    color: var(--light-text);
    margin-bottom: 0.2rem;
}

.info-box p {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-color);
}

/* Responsive for Split Layout */
@media (max-width: 900px) {
    .split-layout {
        flex-direction: column;
    }
}

/* Footer */
.footer {
    background-color: var(--text-color);
    color: var(--white);
    padding: 2rem 0; /* 恢复一点高度给社交图标 */
    text-align: center;
}

/* Social Icons in Footer */
.social-item {
    position: relative;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.3s ease;
}

.social-item:hover {
    transform: translateY(-3px);
}

.social-item i {
    font-size: 1.2rem;
    color: var(--white);
}

.social-item .social-icon {
    width: 44px;
    height: 44px;
    object-fit: contain;
    transition: transform 0.3s ease;
}

.social-item:hover .social-icon {
    transform: scale(1.08);
}

/* QR Popup */
.qr-popup {
    position: absolute;
    bottom: 50px;
    left: 50%;
    transform: translateX(-50%) scale(0);
    background: var(--white);
    padding: 10px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    width: 150px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    z-index: 100;
}

/* 小三角 */
.qr-popup::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 50%;
    transform: translateX(-50%) rotate(45deg);
    width: 12px;
    height: 12px;
    background: var(--white);
}

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

.qr-popup img {
    width: 100%;
    border-radius: 4px;
    display: block;
}

.qr-popup span {
    display: block;
    color: var(--text-color);
    font-size: 0.8rem;
    margin-top: 5px;
    font-weight: 500;
}

.footer-links {
    margin-bottom: 1.5rem;
}

.footer-links a {
    color: #ccc;
    margin: 0 1rem;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--white);
}

.love i {
    color: var(--primary-color);
}

/* Info Sections (Collapsible) */
.info-sections {
    padding: 2rem 0 0 0;
    background-color: #F8F9FA;
}

.collapsible-card {
    background: var(--white);
    border-radius: 20px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    margin-bottom: 2rem;
    overflow: hidden;
    border: 1px solid #eee;
}

.collapsible-header {
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    background: #fff;
    border-bottom: 1px solid transparent;
    transition: all 0.3s;
}

.collapsible-header:hover {
    background: #fcfcfc;
}

.collapsible-header.active {
    border-bottom-color: #f0f0f0;
}

.collapsible-header h2 {
    font-size: 1.5rem;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin: 0;
}

.collapsible-header h2 i {
    color: var(--primary-color);
}

.toggle-wrapper {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--light-text);
}

.toggle-text {
    font-size: 0.9rem;
    font-weight: 500;
}

.toggle-icon {
    transition: transform 0.3s ease;
    color: var(--light-text);
    font-size: 1.2rem;
}

.collapsible-header.active .toggle-icon {
    transform: rotate(180deg);
}

.collapsible-content {
    transition: max-height 0.4s ease-out, opacity 0.4s ease-out;
    max-height: 0;
    overflow: hidden;
    opacity: 0;
}

.collapsible-header.active + .collapsible-content {
    opacity: 1;
}

/* Partial Collapse Styles */
.collapsible-card.partial .collapsible-content {
    max-height: none !important;
    opacity: 1 !important;
    overflow: visible;
}

/* 当 Header 处于非激活状态（即收起）时，隐藏第2个及之后的元素 */
.collapsible-card.partial .collapsible-header:not(.active) + .collapsible-content .timeline-item:nth-child(n+2) {
    display: none;
}

/* Features Detail Styles */
.features-detail {
    padding: 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.feature-detail-item {
    display: flex;
    gap: 1.2rem;
    align-items: flex-start;
}

.feature-detail-item .icon-wrapper {
    width: 50px;
    height: 50px;
    background: #FFF0F0;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.feature-detail-item .icon-wrapper i {
    font-size: 1.4rem;
    color: var(--primary-color);
}

.feature-text h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.feature-text p {
    font-size: 0.95rem;
    color: var(--light-text);
    line-height: 1.6;
}

/* Timeline Styles */
.timeline {
    padding: 2rem 2rem 2rem 3rem;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 2rem;
    top: 2rem;
    bottom: 2rem;
    width: 2px;
    background: #eee;
}

.timeline-item {
    margin-bottom: 2.5rem;
    position: relative;
    padding-left: 2rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: -2.35rem; /* Adjust based on timeline line position */
    top: 0.2rem;
    width: 16px;
    height: 16px;
    background: var(--white);
    border: 3px solid var(--primary-color);
    border-radius: 50%;
    z-index: 1;
}

.timeline-item.major .timeline-dot {
    background: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(255, 107, 107, 0.2);
    border: none;
}

.timeline-date {
    font-size: 0.85rem;
    color: var(--light-text);
    margin-bottom: 0.3rem;
    font-weight: 500;
}

.timeline-content {
    background: #f9f9f9;
    padding: 1rem;
    border-radius: 10px;
}

.timeline-content h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.timeline-content h3 .tag {
    font-size: 0.7rem;
    background: var(--primary-color);
    color: #fff;
    padding: 2px 6px;
    border-radius: 4px;
    font-weight: normal;
}

.timeline-content ul {
    list-style: disc;
    padding-left: 1.2rem;
}

.timeline-content li {
    font-size: 0.95rem;
    color: var(--light-text);
    margin-bottom: 0.3rem;
}

/* Image Protection */
img {
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    user-drag: none;
    pointer-events: none; /* 如果希望完全禁止鼠标交互（如点击放大等），可以使用此属性。如果需要交互，请移除此行 */
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

/* 恢复某些特定图片（如按钮图标、二维码等）的交互能力，如果需要的话 */
.btn-download img, .qr-popup img {
    pointer-events: auto;
}

/* Responsive */
@media (max-width: 768px) {
    .navbar .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        padding: 1rem;
        box-shadow: var(--shadow);
    }

    .navbar .nav-links.active {
        display: flex;
    }

    .hamburger {
        display: block;
    }

    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
    }

    .hero-text h1 {
        font-size: 2.5rem;
    }

    .download-buttons {
        justify-content: center;
    }

    .hero-text p {
        margin: 0 auto 2rem;
    }

    .donation-methods {
        gap: 1rem;
    }

    .method img {
        width: 130px;
        height: 130px;
    }

    .features-detail {
        grid-template-columns: 1fr;
    }
    
    .timeline {
        padding-left: 2rem;
    }
    
    .timeline::before {
        left: 1rem;
    }
    
    .timeline-dot {
        left: -1.35rem;
    }
}