:root {
    --primary-color: #6d28d9;
    --primary-dark: #5b21b6;
    --primary-light: #8b5cf6;
    --accent-color: #14b8a6;
    --accent-dark: #0f766e;
    --text-color: #1e293b;
    --text-muted: #64748b;
    --light-bg: #f8fafc;
    --surface: #ffffff;
    --border-color: #e2e8f0;
    --border-strong: #cbd5e1;
    --hero-bg: linear-gradient(145deg, #4c1d95 0%, #6d28d9 45%, #0f766e 100%);
    --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.06);
    --shadow-md: 0 4px 14px rgba(15, 23, 42, 0.08);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition-speed: 0.25s;
    --transition-easing: cubic-bezier(0.4, 0, 0.2, 1);
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Segoe UI', sans-serif;
    color: var(--text-color);
    line-height: 1.65;
    background: var(--light-bg);
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

/* 导航 */
.z21c13navbar {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    padding: 0.65rem 0;
    box-shadow: none;
}

.z21c13navbar-brand img {
    height: 42px;
    width: auto;
}

.z21c13nav-link {
    color: var(--text-color) !important;
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.45rem 0.85rem !important;
    border-radius: var(--radius-sm);
    transition: color var(--transition-speed), background var(--transition-speed);
}

.z21c13nav-link:hover,
.z21c13nav-link.active {
    color: var(--primary-color) !important;
    background: rgba(109, 40, 217, 0.06);
}

.navbar-toggler {
    border: 1px solid var(--border-color);
    padding: 0.4rem 0.55rem;
}

.navbar-collapse {
    background: var(--surface);
}

/* 英雄区 */
.z21c13hero-section {
    background: var(--hero-bg);
    color: #fff;
    padding: clamp(3rem, 8vw, 5.5rem) 0;
    position: relative;
    overflow: hidden;
}

.z21c13hero-section::after {
    content: '';
    position: absolute;
    right: -10%;
    top: -20%;
    width: 50%;
    height: 140%;
    background: radial-gradient(circle, rgba(255,255,255,0.12) 0%, transparent 65%);
    pointer-events: none;
}

.z21c13hero-content {
    position: relative;
    z-index: 1;
}

.z21c13hero-badge {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    padding: 0.35rem 0.85rem;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.25);
    margin-bottom: 1rem;
}

.z21c13hero-title {
    font-size: clamp(1.75rem, 4vw, 2.75rem);
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.25;
}

.z21c13hero-subtitle {
    font-size: clamp(0.95rem, 2vw, 1.1rem);
    margin-bottom: 1.5rem;
    opacity: 0.92;
    max-width: 36em;
}

.z21c13hero-visual {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.z21c13hero-image {
    width: 100%;
    max-width: 320px;
    margin: 0 auto;
    filter: drop-shadow(0 12px 28px rgba(0, 0, 0, 0.2));
}

.z21c13hero-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.z21c13btn-hero {
    border-radius: var(--radius-md);
    font-weight: 600;
    padding: 0.7rem 1.35rem;
}

.z21c13hero-buttons .btn-light {
    background: #fff;
    color: var(--primary-dark);
    border: none;
}

.z21c13hero-buttons .btn-outline-light {
    border: 1px solid rgba(255, 255, 255, 0.55);
    color: #fff;
}

.z21c13hero-buttons .btn-outline-light:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #fff;
}

.z21c13hero-image-shadow {
    display: none;
}

/* 简介条 */
.z21c13intro-strip {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    padding: 1.25rem 0;
}

.z21c13intro-text {
    font-size: 0.95rem;
    color: var(--text-muted);
    line-height: 1.7;
    text-align: center;
    max-width: 52rem;
    margin-left: auto;
    margin-right: auto;
}

.z21c13intro-text strong {
    color: var(--primary-color);
    font-weight: 600;
}

/* 通用区块 */
.z21c13section {
    padding: clamp(2.5rem, 6vw, 4rem) 0;
}

.z21c13section-head {
    margin-bottom: 2rem;
    max-width: 40rem;
    margin-left: auto;
    margin-right: auto;
}

.z21c13section-head h2 {
    font-size: clamp(1.35rem, 3vw, 1.75rem);
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.z21c13section-head p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* 特点面板 */
.z21c13features-section {
    background: var(--light-bg);
}

.z21c13panel-card {
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    height: 100%;
    box-shadow: var(--shadow-sm);
    transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
    border-left: 3px solid var(--accent-color);
}

.z21c13panel-card:hover {
    border-color: var(--border-strong);
    box-shadow: var(--shadow-md);
}

.z21c13panel-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.65rem;
    color: var(--text-color);
}

.z21c13panel-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0;
    line-height: 1.65;
}

.z21c13panel-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-sm);
    background: rgba(109, 40, 217, 0.1);
    color: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.15rem;
    margin-bottom: 1rem;
}

/* 兼容旧类名 */
.z21c13feature-card {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    height: 100%;
    background: var(--surface);
}

.z21c13feature-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* 统计 */
.z21c13stats-section {
    background: linear-gradient(90deg, var(--primary-dark), var(--primary-color));
    color: #fff;
    padding: clamp(2rem, 5vw, 3rem) 0;
}

.z21c13stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.15);
}

.z21c13stat-item {
    text-align: center;
    padding: 1.25rem 0.75rem;
    background: rgba(0, 0, 0, 0.08);
}

.z21c13stat-number {
    font-size: clamp(1.5rem, 3vw, 2.25rem);
    font-weight: 700;
    margin-bottom: 0.25rem;
    line-height: 1.2;
}

.z21c13stat-label {
    font-size: 0.8rem;
    opacity: 0.9;
    line-height: 1.4;
    padding: 0 0.25rem;
}

/* 下载区 */
.z21c13download-section {
    background: var(--surface);
}

.z21c13download-subtitle {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.z21c13download-card {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--surface);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    height: 100%;
    transition: box-shadow var(--transition-speed);
}

.z21c13download-card:hover {
    box-shadow: var(--shadow-md);
}

.z21c13download-card .card-body {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.z21c13dl-head {
    margin-bottom: 1rem;
}

.z21c13dl-list {
    list-style: none;
    padding: 0;
    margin: 0 0 1.25rem;
    flex: 1;
}

.z21c13dl-list li {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.z21c13dl-list li i {
    color: var(--accent-color);
    margin-top: 0.2rem;
    flex-shrink: 0;
}

.z21c13platform-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.35rem;
    flex-shrink: 0;
}

.z21c13android-icon {
    background: linear-gradient(135deg, #3ddc84, #2bb673);
    color: #fff;
}

.z21c13ios-icon {
    background: linear-gradient(135deg, #0078d4, #005a9e);
    color: #fff;
}

.z21c13download-info {
    background: var(--light-bg);
    padding: 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
}

.z21c13download-action .btn {
    border-radius: var(--radius-sm);
    font-weight: 600;
    padding: 0.65rem 1rem;
}

.btn-primary,
.z21c13btn.btn-primary {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-primary:hover,
.z21c13btn.btn-primary:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
}

/* 知识区 */
.z21c13guide-section {
    background: var(--light-bg);
}

.z21c13knowledge-box {
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    height: 100%;
    box-shadow: var(--shadow-sm);
}

.z21c13knowledge-box h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--primary-color);
}

.z21c13knowledge-box p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    line-height: 1.7;
}

.z21c13knowledge-box p:last-child {
    margin-bottom: 0;
}

/* 安全区 */
.z21c13security-section {
    background: var(--surface);
}

.z21c13security-card {
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    height: 100%;
    text-align: center;
    box-shadow: none;
    transition: border-color var(--transition-speed);
}

.z21c13security-card:hover {
    border-color: var(--primary-light);
    transform: none;
    box-shadow: var(--shadow-sm);
}

.z21c13security-icon {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    margin: 0 auto 0.75rem;
    background: var(--primary-color);
    color: #fff;
}

.z21c13security-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
    text-align: center;
}

.z21c13security-features {
    background: transparent;
    padding: 0;
    border: none;
}

/* FAQ */
.z21c13faq-section {
    background: var(--light-bg);
}

.z21c13faq-card {
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem 1.35rem;
    height: 100%;
}

.z21c13faq-card h5 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.z21c13faq-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
    line-height: 1.65;
}

/* 文章区 */
.z21c13article-section {
    background: var(--surface);
    border-top: 1px solid var(--border-color);
}

.z21c13article-card {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.z21c13thumb-home {
    height: 120px;
    width: 100%;
    object-fit: cover;
}

/* 页脚 */
.z21c13footer {
    background: #1e1b4b;
    color: #cbd5e1;
    padding: clamp(2rem, 5vw, 3rem) 0 1.5rem;
}

.z21c13footer-title {
    color: #e9d5ff;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.z21c13footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.z21c13footer-links li {
    margin-bottom: 0.5rem;
}

.z21c13footer-link {
    color: #94a3b8;
    text-decoration: none;
    font-size: 0.9rem;
    transition: color var(--transition-speed);
}

.z21c13footer-link:hover {
    color: #c4b5fd;
}

.z21c13footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    padding-top: 1.25rem;
    font-size: 0.85rem;
}

.z21c13footer-bottom a {
    color: #a5b4fc;
}

.z21c13friend-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1rem;
    list-style: none;
    padding: 0;
    margin: 0;
}

.z21c13friend-links a {
    color: #94a3b8;
    font-size: 0.85rem;
    text-decoration: none;
}

.z21c13friend-links a:hover {
    color: #c4b5fd;
}

/* 内页 / 列表页 */
.z21c13inner-main {
    padding: clamp(2rem, 5vw, 3rem) 0;
}

.z21c13inner-main .card {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.z21c13article-content {
    font-size: 1rem;
    line-height: 1.8;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.z21c13article-content img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
}

.z21c13meta-tags .z21c13tagitem a {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    font-size: 0.85rem;
    border-radius: 999px;
    background: rgba(109, 40, 217, 0.08);
    color: var(--primary-color);
    text-decoration: none;
}

/* 分页 */
.pagebar .pagelist {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    list-style: none;
    padding-left: 0;
    margin: 0;
}

.pagebar .pagelist li {
    display: inline-flex;
    margin: 0;
}

/* 按钮通用 */
.btn {
    border-radius: var(--radius-sm);
    font-weight: 600;
    transition: transform 0.15s, box-shadow var(--transition-speed);
}

.btn:active {
    transform: scale(0.98);
}

/* 响应式 */
@media (max-width: 991px) {
    .z21c13stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .z21c13navbar .navbar-collapse {
        margin-top: 0.5rem;
        padding: 0.75rem;
        border: 1px solid var(--border-color);
        border-radius: var(--radius-md);
        max-height: 70vh;
        overflow-y: auto;
    }
}

@media (max-width: 767px) {
    .z21c13navbar {
        padding: 0.5rem 0;
    }

    .z21c13navbar .navbar-nav .nav-link {
        padding: 0.5rem 0.35rem !important;
        font-size: 0.92rem;
    }

    .z21c13hero-buttons {
        flex-direction: column;
    }

    .z21c13hero-buttons .btn {
        width: 100%;
        justify-content: center;
    }

    .z21c13stats-grid {
        grid-template-columns: 1fr 1fr;
    }

    .z21c13stat-item {
        padding: 1rem 0.5rem;
    }

    .z21c13stat-label {
        font-size: 0.75rem;
    }

    .z21c13download-section {
        padding-top: 2rem;
        padding-bottom: 2rem;
    }

    .z21c13download-card .card-body {
        padding: 1rem !important;
    }

    .z21c13dl-head {
        flex-direction: row;
        align-items: flex-start !important;
    }

    .z21c13download-action .btn {
        width: 100%;
        white-space: normal;
        text-align: center;
    }

    .z21c13panel-card,
    .z21c13knowledge-box,
    .z21c13security-card,
    .z21c13faq-card {
        padding: 1.1rem;
    }

    .z21c13thumb-home {
        height: 96px !important;
    }

    #article .card-body,
    .z21c13article-card .card-body {
        padding: 0.75rem;
    }

    #article h3.h6,
    #article h3.h5 {
        font-size: 0.92rem;
        line-height: 1.4;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        overflow: hidden;
    }

    .listbox .e2 li {
        padding-bottom: 0.75rem !important;
        margin-bottom: 0.75rem !important;
    }

    .listbox .e2 li h2.h5 {
        font-size: 1rem;
        line-height: 1.35;
    }

    .z21c13thumb-list,
    .z21c13thumb-related {
        height: 72px !important;
    }

    .z21c13thumb-side {
        height: 50px !important;
    }

    .z21c13thumb-cover {
        max-width: 100% !important;
        width: 100%;
        height: 170px !important;
    }

    .z21c13footer .row > [class*="col-"] {
        text-align: center;
    }

    .z21c13footer-links {
        margin-bottom: 0.5rem;
    }
}

@media (max-width: 575px) {
    .z21c13stats-grid {
        grid-template-columns: 1fr;
    }

    .z21c13intro-text {
        font-size: 0.88rem;
        text-align: left;
    }

    .z21c13thumb-home {
        height: 88px !important;
    }

    .z21c13thumb-list,
    .z21c13thumb-related {
        height: 64px !important;
    }

    .z21c13thumb-cover {
        height: 150px !important;
    }

    .pagebar .pagelist {
        gap: 0.35rem;
    }
}

/* 去除旧版过大阴影与动画，防止边框挤出 */
.z21c13security-certificates,
.z21c13certificate-card {
    display: none;
}

.app-preview-container,
.app-screen {
    display: none;
}