/* 纸飞机官网 — 单文件样式 */
:root {
    --primary: #5b4b8a;
    --primary-dark: #3d3260;
    --accent: #2ec4b6;
    --accent-soft: rgba(46, 196, 182, 0.12);
    --warm: #ff9f1c;
    --text: #1a1d26;
    --text-muted: #5c6370;
    --surface: #ffffff;
    --surface-alt: #f4f6fb;
    --border: #e2e6ef;
    --radius: 12px;
    --radius-lg: 20px;
    --shadow: 0 4px 24px rgba(45, 55, 90, 0.08);
    --shadow-hover: 0 12px 32px rgba(45, 55, 90, 0.12);
    --nav-h: 72px;
    --transition: 0.25s ease;
}

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

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

body {
    font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
    color: var(--text);
    line-height: 1.65;
    background: var(--surface);
    overflow-x: hidden;
}

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

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    color: var(--accent);
}

/* —— 导航 —— */
.zbf3c6navbar {
    position: sticky;
    top: 0;
    z-index: 1030;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    padding: 0.65rem 0;
    min-height: var(--nav-h);
}

.zbf3c6navbar-brand img {
    height: 42px;
    width: auto;
}

.zbf3c6nav-link {
    color: var(--text) !important;
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.45rem 0.85rem !important;
    border-radius: 8px;
    transition: background var(--transition), color var(--transition);
}

.zbf3c6nav-link:hover,
.zbf3c6nav-item.active .zbf3c6nav-link {
    color: var(--primary) !important;
    background: var(--accent-soft);
}

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

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

@media (max-width: 991px) {
    .navbar-collapse {
        margin-top: 0.75rem;
        padding: 0.75rem;
        border-radius: var(--radius);
        border: 1px solid var(--border);
        max-height: 70vh;
        overflow-y: auto;
    }

    .zbf3c6nav-link {
        padding: 0.5rem 0.35rem !important;
    }
}

/* —— 通用区块 —— */
.pg-section {
    padding: 4.5rem 0;
}

.pg-section--alt {
    background: var(--surface-alt);
}

.pg-head {
    max-width: 640px;
    margin: 0 auto 2.5rem;
    text-align: center;
}

.pg-head h2 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 0.75rem;
}

.pg-head p {
    color: var(--text-muted);
    margin: 0;
    font-size: 1.05rem;
}

.pg-label {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    background: var(--accent-soft);
    padding: 0.35rem 0.85rem;
    border-radius: 999px;
    margin-bottom: 0.85rem;
}

/* —— Hero —— */
.zbf3c6hero-section {
    padding: 3.5rem 0 4rem;
    background: linear-gradient(145deg, var(--primary-dark) 0%, var(--primary) 45%, #6b5b9a 100%);
    color: #fff;
    position: relative;
    overflow: hidden;
}

.zbf3c6hero-section::after {
    content: "";
    position: absolute;
    width: 480px;
    height: 480px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(46, 196, 182, 0.25) 0%, transparent 70%);
    top: -120px;
    right: -80px;
    pointer-events: none;
}

.zbf3c6hero-content {
    position: relative;
    z-index: 1;
}

.zbf3c6hero-title {
    font-size: clamp(1.85rem, 4.5vw, 2.75rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
}

.zbf3c6hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.15rem);
    opacity: 0.92;
    margin-bottom: 1.75rem;
    max-width: 520px;
}

.zbf3c6hero-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.zbf3c6hero-buttons .btn {
    border-radius: 10px;
    font-weight: 600;
    padding: 0.7rem 1.35rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    white-space: normal;
}

.zbf3c6hero-buttons .btn-light {
    background: #fff;
    color: var(--primary-dark);
    border: none;
}

.zbf3c6hero-buttons .btn-light:hover {
    background: #f0f0f5;
    transform: translateY(-2px);
}

.zbf3c6hero-buttons .btn-primary,
.zbf3c6btn.btn-primary {
    background: var(--accent);
    border: none;
    color: #fff;
}

.zbf3c6hero-buttons .btn-primary:hover,
.zbf3c6btn.btn-primary:hover {
    background: #25a99d;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(46, 196, 182, 0.35);
}

.zbf3c6hero-image-container {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.zbf3c6hero-image {
    max-width: 280px;
    width: 100%;
    border-radius: var(--radius-lg);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.25);
    margin: 0 auto;
}

.zbf3c6hero-image-shadow {
    display: none;
}

/* —— 亮点 Bento —— */
#features .bento-grid {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    gap: 1.25rem;
}

.bento-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    height: 100%;
    box-shadow: var(--shadow);
    transition: box-shadow var(--transition), border-color var(--transition);
    overflow: hidden;
}

.bento-card:hover {
    box-shadow: var(--shadow-hover);
    border-color: rgba(46, 196, 182, 0.35);
}

.bento-card--wide {
    grid-column: span 7;
}

.bento-card--narrow {
    grid-column: span 5;
}

.bento-card--third {
    grid-column: span 4;
}

.bento-icon {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    background: var(--accent-soft);
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.35rem;
    margin-bottom: 1rem;
}

.bento-card h3 {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 0.65rem;
}

.bento-card p {
    color: var(--text-muted);
    margin: 0;
    font-size: 0.95rem;
}

/* —— 知识区 —— */
.knowledge-wrap {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    align-items: start;
}

.knowledge-main {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow);
}

.knowledge-main h3 {
    font-size: 1.2rem;
    color: var(--primary-dark);
    margin-bottom: 1rem;
}

.knowledge-main p {
    color: var(--text-muted);
    margin-bottom: 1rem;
    font-size: 0.98rem;
}

.knowledge-main p:last-child {
    margin-bottom: 0;
}

.knowledge-aside {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.knowledge-tip {
    background: var(--surface);
    border-left: 4px solid var(--accent);
    border-radius: 0 var(--radius) var(--radius) 0;
    padding: 1.15rem 1.25rem;
    border-top: 1px solid var(--border);
    border-right: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.knowledge-tip strong {
    display: block;
    color: var(--primary-dark);
    margin-bottom: 0.35rem;
    font-size: 0.95rem;
}

.knowledge-tip span {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* —— 统计 —— */
.zbf3c6stats-section {
    padding: 3rem 0;
    background: var(--primary-dark);
    color: #fff;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.zbf3c6stat-item {
    text-align: center;
    padding: 1.25rem 0.75rem;
    border-radius: var(--radius);
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: rgba(255, 255, 255, 0.05);
}

.zbf3c6stat-number {
    font-size: clamp(1.75rem, 3vw, 2.5rem);
    font-weight: 800;
    color: var(--accent);
    line-height: 1.2;
    margin-bottom: 0.35rem;
}

.zbf3c6stat-label {
    font-size: 0.9rem;
    opacity: 0.88;
}

/* —— 下载 —— */
.zbf3c6download-section {
    padding: 4.5rem 0;
    background: var(--surface-alt);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem;
    max-width: 900px;
    margin: 0 auto;
}

.zbf3c6download-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    height: 100%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: box-shadow var(--transition);
}

.zbf3c6download-card:hover {
    box-shadow: var(--shadow-hover);
}

.zbf3c6download-card .card-body {
    padding: 1.5rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.zbf3c6download-card .d-flex.align-items-center {
    margin-bottom: 1rem;
}

.zbf3c6platform-icon {
    width: 52px;
    height: 52px;
    min-width: 52px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    color: #fff;
}

.zbf3c6ios-icon {
    background: linear-gradient(135deg, #0078d4, #005a9e);
}

.zbf3c6android-icon {
    background: linear-gradient(135deg, #3ddc84, #2a9d5c);
}

.zbf3c6download-info {
    background: var(--accent-soft);
    padding: 1rem 1.15rem;
    border-radius: var(--radius);
    margin-bottom: 1rem;
    flex: 1;
}

.zbf3c6info-item {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.zbf3c6info-item:last-child {
    margin-bottom: 0;
}

.zbf3c6info-item i {
    color: var(--accent);
    margin-top: 0.15rem;
    flex-shrink: 0;
}

.zbf3c6download-action {
    margin-top: auto;
}

.zbf3c6download-action .btn {
    width: 100%;
    border-radius: 10px;
    padding: 0.65rem 1rem;
    font-weight: 600;
    white-space: normal;
}

/* —— 安全 —— */
.zbf3c6security-section {
    padding: 4.5rem 0;
}

.security-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.zbf3c6security-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    height: 100%;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    text-align: center;
}

.zbf3c6security-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 1rem;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.zbf3c6security-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 0.85rem;
}

.zbf3c6security-features {
    background: var(--surface-alt);
    border-radius: var(--radius);
    padding: 0.85rem 1rem;
    text-align: left;
    flex: 1;
}

.zbf3c6feature-item {
    display: flex;
    align-items: flex-start;
    gap: 0.45rem;
    margin-bottom: 0.45rem;
    font-size: 0.88rem;
    color: var(--text-muted);
}

.zbf3c6feature-item:last-child {
    margin-bottom: 0;
}

.zbf3c6feature-item i {
    color: var(--accent);
    flex-shrink: 0;
    margin-top: 0.1rem;
}

.cert-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-top: 2rem;
}

.zbf3c6certificate-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    text-align: center;
    height: 100%;
    box-shadow: var(--shadow);
}

.zbf3c6certificate-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 0.85rem;
    border-radius: 50%;
    background: var(--accent-soft);
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
}

.zbf3c6certificate-card h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 0.4rem;
}

.zbf3c6certificate-card p {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin: 0;
}

/* —— FAQ —— */
.faq-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

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

.faq-card h5 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 0.5rem;
}

.faq-card p {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin: 0;
}

/* —— 文章区 —— */
#article {
    padding: 4rem 0;
    background: var(--surface-alt);
}

#article .card {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    height: 100%;
}

#article .card-img-top,
.zbf3c6thumb-home {
    width: 100%;
    height: 120px;
    object-fit: cover;
}

#article .card-body {
    padding: 0.85rem 1rem;
}

#article h3.h5 {
    font-size: 0.95rem;
    line-height: 1.4;
    margin: 0;
}

#article h3.h5 a {
    color: var(--text);
}

#article h3.h5 a:hover {
    color: var(--primary);
}

.btn-outline-primary.zbf3c6btn {
    border-color: var(--primary);
    color: var(--primary);
    border-radius: 10px;
}

.btn-outline-primary.zbf3c6btn:hover {
    background: var(--primary);
    border-color: var(--primary);
    color: #fff;
}

/* —— 页脚 —— */
.zbf3c6footer {
    background: var(--primary-dark);
    color: rgba(255, 255, 255, 0.85);
    padding: 3rem 0 1.5rem;
}

.zbf3c6footer-title {
    color: #fff;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.zbf3c6footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.zbf3c6footer-links li {
    margin-bottom: 0.5rem;
}

.zbf3c6footer-link {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9rem;
}

.zbf3c6footer-link:hover {
    color: var(--accent);
}

.zbf3c6footer p {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.65);
}

.zbf3c6friend-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1rem;
    list-style: none;
    padding: 0;
    margin: 0;
}

.zbf3c6friend-links a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.88rem;
}

.zbf3c6friend-links a:hover {
    color: var(--accent);
}

.zbf3c6footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    padding-top: 1.25rem;
    margin-top: 2rem;
    text-align: center;
}

.zbf3c6footer-bottom a {
    color: rgba(255, 255, 255, 0.75);
}

.zbf3c6footer-bottom a:hover {
    color: var(--accent);
}

/* —— 列表/内页 —— */
.page-hero-bar {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    color: #fff;
    padding: 2rem 0;
    margin-bottom: 0;
}

.page-hero-bar h1 {
    font-size: clamp(1.25rem, 3vw, 1.65rem);
    font-weight: 700;
    margin-bottom: 0.35rem;
}

.page-hero-bar p {
    opacity: 0.88;
    margin: 0;
    font-size: 0.95rem;
}

.list-page .card,
.article-page .card {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.zbf3c6article-content {
    line-height: 1.8;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.zbf3c6article-content img {
    max-width: 100%;
    height: auto;
}

.zbf3c6thumb-list,
.zbf3c6thumb-related {
    width: 100%;
    height: 84px;
    object-fit: cover;
    border-radius: var(--radius);
}

.zbf3c6thumb-side {
    width: 100%;
    height: 54px;
    object-fit: cover;
    border-radius: 8px;
}

.zbf3c6thumb-cover {
    max-width: 100%;
    width: 100%;
    height: auto;
    max-height: 320px;
    object-fit: cover;
    border-radius: var(--radius);
}

.pagebar .pagelist {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    list-style: none;
    padding: 0;
    margin: 0;
}

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

/* —— 响应式 —— */
@media (max-width: 1199px) {
    .bento-card--wide,
    .bento-card--narrow {
        grid-column: span 6;
    }

    .bento-card--third {
        grid-column: span 6;
    }

    .security-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 991px) {
    .pg-section {
        padding: 3.5rem 0;
    }

    .knowledge-wrap {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    #article .row-cols-lg-5 > .col {
        flex: 0 0 33.333%;
        max-width: 33.333%;
    }
}

@media (max-width: 767px) {
    .zbf3c6hero-section {
        padding: 2.5rem 0 3rem;
        text-align: center;
    }

    .zbf3c6hero-subtitle {
        margin-left: auto;
        margin-right: auto;
    }

    .zbf3c6hero-buttons {
        justify-content: center;
    }

    .zbf3c6hero-buttons .btn {
        width: 100%;
        max-width: 320px;
    }

    .zbf3c6hero-image {
        max-width: 220px;
        margin-top: 1.5rem;
    }

    #features .bento-grid {
        grid-template-columns: 1fr;
    }

    .bento-card--wide,
    .bento-card--narrow,
    .bento-card--third {
        grid-column: span 1;
    }

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

    .zbf3c6download-card .d-flex.align-items-center {
        flex-wrap: wrap;
    }

    .zbf3c6download-card .d-flex.align-items-center .ms-3 {
        margin-left: 0 !important;
        width: 100%;
    }

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

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

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }

    .zbf3c6stat-item {
        padding: 1rem 0.5rem;
    }

    .knowledge-main {
        padding: 1.35rem;
    }

    #article .row-cols-md-2 > .col,
    #article .row-cols-lg-5 > .col {
        flex: 0 0 50%;
        max-width: 50%;
    }

    #article .zbf3c6thumb-home {
        height: 96px !important;
    }

    .zbf3c6thumb-list,
    .zbf3c6thumb-related {
        height: 72px !important;
    }

    .zbf3c6thumb-cover {
        max-height: 200px;
    }

    .zbf3c6footer .row > [class*="col-"] {
        text-align: center;
        margin-bottom: 1.5rem;
    }
}

@media (max-width: 575px) {
    .pg-section {
        padding: 2.75rem 0;
    }

    .pg-head {
        margin-bottom: 1.75rem;
    }

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

    #article .row-cols-md-2 > .col,
    #article .row-cols-lg-5 > .col {
        flex: 0 0 100%;
        max-width: 100%;
    }

    #article .d-flex.justify-content-between {
        flex-direction: column;
        align-items: flex-start !important;
        gap: 0.75rem;
    }

    .listbox .e2 li .row {
        flex-direction: column;
    }

    .listbox .e2 li .col-4,
    .listbox .e2 li .col-8 {
        width: 100%;
        max-width: 100%;
    }

    .zbf3c6thumb-list {
        height: 140px !important;
        margin-bottom: 0.5rem;
    }

    .pagebar .pagelist {
        justify-content: center;
    }
}

/* 兼容旧类名 */
.zbf3c6feature-card { display: none; }
.zbf3c6download-header h2,
.zbf3c6security-header h2 { color: var(--primary-dark); font-weight: 700; }
.zbf3c6download-subtitle,
.zbf3c6security-subtitle { color: var(--text-muted); }