/* ===== 基础变量 ===== */
:root {
    /* PDFgear 品牌色：橙红渐变 */
    --color-primary: #FF5A1F;
    --color-primary-dark: #E04510;
    --color-primary-light: #FF7A45;
    --color-accent: #FF8A3D;
    --color-glow: rgba(255, 90, 31, 0.35);

    --color-dark: #1A1A1A;
    --color-dark-2: #242424;
    --color-dark-3: #2D2D2D;
    --color-text: #1A1A1A;
    --color-text-light: #555;
    --color-text-muted: #888;
    --color-bg: #FFFFFF;
    --color-bg-soft: #FAFAFA;
    --color-bg-dark: #0F0F0F;
    --color-border: #EAEAEA;

    --gradient-primary: linear-gradient(135deg, #FF5A1F 0%, #FF8A3D 100%);
    --gradient-hero: radial-gradient(ellipse at top right, rgba(255, 90, 31, 0.12) 0%, transparent 60%);

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.12);
    --shadow-primary: 0 12px 32px rgba(255, 90, 31, 0.35);

    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 24px;
    --radius-full: 999px;

    --container: 1200px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Reset ===== */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

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

button {
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
}

/* ===== 容器 ===== */
.container {
    width: 100%;
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 通用按钮 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: var(--radius-full);
    font-size: 15px;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
    white-space: nowrap;
}

.btn-lg {
    padding: 16px 36px;
    font-size: 16px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #fff;
    box-shadow: var(--shadow-primary);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 16px 40px rgba(255, 90, 31, 0.45);
}

.btn-ghost {
    background: transparent;
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

.btn-ghost:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    transform: translateY(-3px);
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(234, 234, 234, 0.6);
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    font-size: 22px;
}

.logo-img {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    background: var(--gradient-primary);
    object-fit: contain;
}

.logo-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.5px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    padding: 8px 18px;
    border-radius: var(--radius-full);
    font-size: 15px;
    font-weight: 500;
    color: var(--color-text-light);
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--color-primary);
    background: rgba(255, 90, 31, 0.08);
}

.nav-download {
    background: var(--gradient-primary);
    color: #fff !important;
    box-shadow: 0 6px 16px rgba(255, 90, 31, 0.3);
}

.nav-download:hover {
    background: var(--gradient-primary);
    transform: translateY(-2px);
    box-shadow: 0 10px 24px rgba(255, 90, 31, 0.4);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 6px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ===== Hero 首屏 ===== */
.hero {
    position: relative;
    padding: 140px 0 80px;
    background: var(--color-bg-soft);
    background-image: var(--gradient-hero);
    overflow: hidden;
}

.hero::before {
    content: "";
    position: absolute;
    top: -200px;
    right: -200px;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 90, 31, 0.15) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-badge {
    display: inline-block;
    padding: 7px 18px;
    background: rgba(255, 90, 31, 0.1);
    color: var(--color-primary);
    border-radius: var(--radius-full);
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 24px;
}

.hero-title {
    font-size: clamp(36px, 5vw, 56px);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -1.5px;
    margin-bottom: 24px;
}

.highlight {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    font-size: 17px;
    color: var(--color-text-light);
    line-height: 1.75;
    margin-bottom: 32px;
    max-width: 540px;
}

.hero-meta {
    display: flex;
    align-items: center;
    gap: 24px;
    padding: 20px 24px;
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.meta-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.meta-label {
    font-size: 12px;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.meta-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-text);
}

.meta-divider {
    width: 1px;
    height: 32px;
    background: var(--color-border);
}

.hero-platforms {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 36px;
}

.platforms-label {
    font-size: 14px;
    color: var(--color-text-muted);
    margin-right: 4px;
}

.platform-tag {
    padding: 5px 14px;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    font-size: 13px;
    font-weight: 600;
    color: var(--color-text);
    transition: var(--transition);
}

.platform-tag:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-visual {
    position: relative;
}

.hero-image {
    width: 100%;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    aspect-ratio: 16 / 11;
    object-fit: cover;
}

.hero-glow {
    position: absolute;
    inset: -30px;
    background: radial-gradient(circle at center, rgba(255, 90, 31, 0.2) 0%, transparent 70%);
    border-radius: var(--radius-lg);
    z-index: -1;
    filter: blur(40px);
}

/* ===== 信任标识 ===== */
.trust-section {
    padding: 50px 0;
    background: #fff;
    border-bottom: 1px solid var(--color-border);
}

.trust-text {
    text-align: center;
    font-size: 14px;
    color: var(--color-text-muted);
    margin-bottom: 32px;
    letter-spacing: 0.5px;
}

.trust-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    max-width: 800px;
    margin: 0 auto;
}

.stat {
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.stat-num {
    font-size: clamp(28px, 4vw, 40px);
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1;
}

.stat-label {
    font-size: 14px;
    color: var(--color-text-muted);
}

/* ===== 通用区块 ===== */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 60px;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(255, 90, 31, 0.1);
    color: var(--color-primary);
    border-radius: var(--radius-full);
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 16px;
    letter-spacing: 0.5px;
}

.section-title {
    font-size: clamp(28px, 4vw, 42px);
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: 16px;
    line-height: 1.2;
}

.section-subtitle {
    font-size: 16px;
    color: var(--color-text-light);
}

/* ===== 功能特点 ===== */
.features {
    background: var(--color-bg-soft);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.feature-card {
    background: #fff;
    padding: 32px 28px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid transparent;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-md);
    border-color: rgba(255, 90, 31, 0.2);
}

.feature-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    background: rgba(255, 90, 31, 0.1);
    border-radius: var(--radius-md);
    margin-bottom: 20px;
}

.feature-title {
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 12px;
}

.feature-desc {
    font-size: 14px;
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===== 用户评价 ===== */
.reviews {
    background: #fff;
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.review-card {
    background: var(--color-bg-soft);
    padding: 32px 28px;
    border-radius: var(--radius-md);
    transition: var(--transition);
    border: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
}

.review-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(255, 90, 31, 0.2);
}

.review-stars {
    color: #FFB400;
    font-size: 16px;
    letter-spacing: 2px;
    margin-bottom: 16px;
}

.review-text {
    font-size: 15px;
    line-height: 1.75;
    color: var(--color-text);
    margin-bottom: 24px;
    flex: 1;
    font-style: italic;
}

.review-author {
    display: flex;
    flex-direction: column;
    gap: 2px;
    padding-top: 16px;
    border-top: 1px solid var(--color-border);
}

.review-author strong {
    font-size: 15px;
    color: var(--color-primary);
}

.review-author span {
    font-size: 13px;
    color: var(--color-text-muted);
}

/* ===== 常见问题 ===== */
.faq {
    background: var(--color-bg-soft);
}

.faq-list {
    max-width: 820px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: var(--transition);
    border: 1px solid var(--color-border);
}

.faq-item.active {
    border-color: rgba(255, 90, 31, 0.3);
    box-shadow: var(--shadow-md);
}

.faq-question {
    width: 100%;
    padding: 22px 28px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    font-size: 16px;
    font-weight: 600;
    color: var(--color-text);
    text-align: left;
    transition: var(--transition);
}

.faq-question:hover {
    color: var(--color-primary);
}

.faq-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 90, 31, 0.1);
    color: var(--color-primary);
    border-radius: 50%;
    font-size: 18px;
    font-weight: 700;
    transition: var(--transition);
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
    background: var(--gradient-primary);
    color: #fff;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
}

.faq-answer p {
    padding: 0 28px 24px;
    font-size: 15px;
    color: var(--color-text-light);
    line-height: 1.75;
}

/* ===== 下载区域 ===== */
.download {
    background: var(--color-bg-dark);
    position: relative;
    overflow: hidden;
}

.download::before {
    content: "";
    position: absolute;
    top: -100px;
    left: 50%;
    transform: translateX(-50%);
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(255, 90, 31, 0.25) 0%, transparent 60%);
    border-radius: 50%;
    pointer-events: none;
}

.download-card {
    position: relative;
    text-align: center;
    padding: 80px 40px;
    background: linear-gradient(135deg, rgba(255, 90, 31, 0.12) 0%, rgba(255, 138, 61, 0.06) 100%);
    border: 1px solid rgba(255, 90, 31, 0.25);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
}

.download-card .section-tag {
    background: rgba(255, 90, 31, 0.2);
    color: var(--color-accent);
}

.download-title {
    font-size: clamp(32px, 4.5vw, 48px);
    font-weight: 800;
    color: #fff;
    margin-bottom: 16px;
    letter-spacing: -1px;
}

.download-subtitle {
    font-size: 17px;
    color: rgba(255, 255, 255, 0.75);
    margin-bottom: 40px;
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: 16px;
    padding: 20px 48px;
    background: var(--gradient-primary);
    color: #fff;
    border-radius: var(--radius-full);
    box-shadow: 0 20px 50px rgba(255, 90, 31, 0.5);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn-download::before {
    content: "";
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.6s;
}

.btn-download:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 24px 60px rgba(255, 90, 31, 0.6);
}

.btn-download:hover::before {
    left: 100%;
}

.btn-download-icon {
    font-size: 28px;
    line-height: 1;
}

.btn-download-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 2px;
}

.btn-download-label {
    font-size: 20px;
    font-weight: 700;
}

.btn-download-version {
    font-size: 12px;
    opacity: 0.85;
}

.download-platforms {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    margin-top: 48px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.download-platform {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 20px 12px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.download-platform:hover {
    background: rgba(255, 90, 31, 0.15);
    border-color: rgba(255, 90, 31, 0.4);
    transform: translateY(-3px);
}

.platform-icon {
    font-size: 28px;
}

.platform-name {
    font-size: 15px;
    font-weight: 600;
    color: #fff;
}

.platform-info {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.6);
}

.download-note {
    margin-top: 32px;
    font-size: 13px;
    color: rgba(255, 255, 255, 0.5);
}

/* ===== 页脚 ===== */
.footer {
    background: #0A0A0A;
    color: rgba(255, 255, 255, 0.7);
    padding: 60px 0 24px;
}

.footer-top {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand .logo {
    margin-bottom: 16px;
}

.footer-brand .logo-text {
    color: #fff;
    -webkit-text-fill-color: #fff;
    background: none;
}

.footer-desc {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    max-width: 360px;
    line-height: 1.7;
}

.footer-links {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.footer-col h4 {
    color: #fff;
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-col a {
    display: block;
    padding: 6px 0;
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    transition: var(--transition);
}

.footer-col a:hover {
    color: var(--color-accent);
    padding-left: 4px;
}

.footer-bottom {
    padding-top: 24px;
    text-align: center;
    font-size: 13px;
    color: rgba(255, 255, 255, 0.4);
}

/* ===== 滚动出现动画 ===== */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .hero-container {
        gap: 40px;
    }
}

@media (max-width: 768px) {
    section {
        padding: 70px 0;
    }

    .hero {
        padding: 110px 0 60px;
    }

    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: stretch;
        padding: 16px;
        gap: 4px;
        box-shadow: var(--shadow-md);
        transform: translateY(-150%);
        transition: transform 0.4s ease;
        max-height: calc(100vh - 72px);
        overflow-y: auto;
    }

    .nav-menu.active {
        transform: translateY(0);
    }

    .nav-link {
        padding: 14px 18px;
        font-size: 16px;
    }

    .menu-toggle {
        display: flex;
    }

    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: left;
    }

    .hero-visual {
        order: -1;
    }

    .hero-meta {
        gap: 16px;
        padding: 16px 18px;
    }

    .meta-divider {
        display: none;
    }

    .hero-actions {
        flex-direction: column;
    }

    .hero-actions .btn {
        width: 100%;
    }

    .trust-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 32px;
    }

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

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

    .footer-top {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .btn-download {
        padding: 16px 32px;
        flex-direction: column;
        gap: 8px;
    }

    .download-card {
        padding: 50px 24px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

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

    .hero-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }

    .meta-item {
        flex-direction: row;
        align-items: center;
        gap: 12px;
        width: 100%;
        justify-content: space-between;
    }

    .btn-download {
        width: 100%;
    }
}

/* ===== 小屏调整文字 ===== */
@media (max-width: 360px) {
    .hero-title {
        font-size: 32px;
    }

    .section-title {
        font-size: 26px;
    }
}