:root {
    --blue: #4179ff;
    --text: #333;
    --muted: #999;
    --button: linear-gradient(100deg, #199ef5, #4173ff);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 104px; }
body { margin: 0; isolation: isolate; color: var(--text); background: #fff; font-family: "Microsoft YaHei", "PingFang SC", sans-serif; }
/* 背景固定占满可视窗口，各区块透明并在背景上方正常滚动。 */
body::before { content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none; background: #fff url("dll/background.png") center / cover no-repeat; }
button, a { -webkit-tap-highlight-color: transparent; }
button { font: inherit; cursor: pointer; }
a { color: inherit; text-decoration: none; }
button:disabled { cursor: wait; opacity: .65; }
button:focus-visible, a:focus-visible { outline: 3px solid #2251d7; outline-offset: 5px; }
[hidden] { display: none !important; }
.svg-symbols { position: absolute; width: 0; height: 0; overflow: hidden; }
.container { width: min(1280px, calc(100% - 64px)); margin-inline: auto; }
.site-header { position: sticky; top: 0; z-index: 10; height: 80px; background: rgba(255,255,255,.95); box-shadow: 0 3px 14px #1f354508; }
.header-inner { display: flex; height: 100%; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: flex; align-items: center; gap: 12px; flex-shrink: 0; font-size: 23px; letter-spacing: 1px; }
.brand img { border-radius: 3px; }
.brand small { display: block; margin-top: 3px; font-size: 12px; color: var(--muted); letter-spacing: 0; }
nav { display: flex; flex: 1; align-items: center; justify-content: space-around; gap: 20px; font-size: 18px; }
.nav-download.download-button { padding: 0; background: none; color: var(--text); font-size: inherit; white-space: nowrap; }
.nav-download.download-button:hover { color: var(--blue); }
.download-button { display: inline-flex; justify-content: center; align-items: center; gap: 9px; padding: 10px 18px; border: 0; border-radius: 3px; background: var(--button); color: #fff; font-size: 20px; line-height: 26px; }
.download-button svg { width: 22px; height: 22px; flex-shrink: 0; }
.download-button:hover { filter: brightness(1.04); }
.hero { min-height: 1000px; }
.hero-main { height: 650px; position: relative; }
.hero-copy { padding-top: 119px; position: relative; z-index: 2; width: 550px; }
h1 { position: relative; display: inline-block; margin: 0; font-size: 50px; line-height: 1.4; font-weight: 700; white-space: nowrap; }
h1 > span { color: var(--blue); }
h1 small { position: absolute; left: calc(100% + 10px); top: -12px; padding: 5px 12px; border-radius: 18px 0 18px 0; background: linear-gradient(110deg,#c963ec,#ed6fdf); color: white; font-size: 18px; line-height: 26px; }
.hero-description { margin: 13px 0 35px; font-size: 26px; line-height: 1.85; }
.hero-download { width: 400px; height: 80px; font-size: 26px; font-weight: 600; }
.hero-download svg { width: 26px; height: 26px; }
.system-note { margin: 11px 0 16px; width: 400px; text-align: center; color: var(--muted); font-size: 12px; }
.statistics { width: 400px; text-align: center; font-size: 22px; }
.statistics strong { color: var(--blue); margin-inline: 5px; }
.hero-visual { position: absolute; top: 92px; right: -15px; width: 710px; }
.product-preview { display: block; width: 100%; height: auto; filter: drop-shadow(0 0 10px #2c435523); }
.error-preview { position: absolute; width: 332px; height: auto; left: -73px; top: 303px; }
.repair-result { position: absolute; right: -55px; top: -56px; width: 230px; height: 110px; padding: 25px 15px; border: 1px solid #fff; border-radius: 7px; background: #f4faff; text-align: center; box-shadow: 0 0 15px #435f8226; }
.repair-result > div { color: var(--blue); font-size: 18px; }
.checkmark { display: inline-grid; place-items: center; width: 26px; height: 26px; margin-right: 8px; border-radius: 50%; background: #2c94ff; color: white; font-weight: bold; }
.repair-result p { font-size: 12px; color: #666; margin: 13px 0 0; }
.repair-result em { color: var(--blue); font-style: normal; }
.feature-grid { display: flex; justify-content: space-between; padding-top: 18px; padding-bottom: 72px; }
.feature { width: 220px; text-align: center; scroll-margin-top: 100px; }
.feature-image { height: 140px; display: flex; justify-content: center; align-items: end; }
.feature img { max-width: 200px; max-height: 137px; object-fit: contain; }
.feature h2 { margin: 18px 0 8px; font-size: 24px; font-weight: 500; }
.feature p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.8; }
.common-files { padding: 33px 0 55px; }
.section-title { display: flex; align-items: center; justify-content: center; gap: 40px; margin: 0; font-size: 38px; line-height: 1.5; font-weight: 600; }
.section-title::before, .section-title::after { content: ""; width: 154px; height: 2px; background: linear-gradient(90deg, transparent, var(--blue)); }
.section-title::after { transform: scaleX(-1); }
.section-description { margin: 20px 0 62px; color: #666; text-align: center; font-size: 20px; }
.file-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px 20px; }
.file-card { min-width: 0; height: 86px; padding: 18px 20px; justify-content: space-between; text-align: left; background: #ffffffeb; color: #333; box-shadow: 0 0 18px #40516a12; }
.file-card .file-name { font-size: 16px; }
.file-name b { display: inline-block; padding: 0 3px; border-radius: 2px; background: var(--button); color: white; font-size: 10px; line-height: 16px; vertical-align: 2px; }
.file-card small { display: block; color: var(--muted); font-size: 14px; line-height: 22px; }
.file-card svg { width: 20px; height: 20px; color: var(--muted); }
.all-files { display: flex; width: fit-content; margin: 32px auto 0; padding: 3px 12px; border: 1px solid #eee; background: #fff; color: #888; font-size: 13px; }
.repair-steps { padding-top: 90px; padding-bottom: 70px; }
.steps-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 80px; margin-top: 56px; }
.step { position: relative; display: flex; align-items: center; gap: 16px; height: 116px; padding: 20px 25px; border-radius: 4px; box-shadow: 0 0 10px #5161722e; background: #fff; }
.step:not(:last-child)::after { content: ""; position: absolute; right: -53px; width: 23px; height: 25px; background: url("dll/step-arrow.png") center / contain no-repeat; }
.step-number { display: grid; flex: 0 0 28px; place-items: center; width: 28px; height: 28px; color: #fff; background: var(--button); border-radius: 50%; font-size: 20px; }
.step h3 { font-size: 20px; font-weight: 500; margin: 0 0 10px; }
.step p { font-size: 13px; white-space: nowrap; color: var(--muted); margin: 0; }
.step img { margin-left: auto; width: 80px; height: auto; }
.reviews { padding: 92px 0 74px; }
.reviews .section-description { margin: 16px 20px 60px; font-size: 16px; }
.review-marquee { max-width: 1600px; margin-inline: auto; overflow: hidden; mask-image: linear-gradient(90deg, transparent, #000 10%, #000 90%, transparent); }
.review-row { overflow: hidden; margin-bottom: 22px; }
.review-row:last-child { margin-bottom: 0; }
/* 两份等宽内容首尾相接，移动一组宽度即可无缝循环。 */
.review-track { width: max-content; display: flex; animation: reviews-scroll 36s linear infinite; }
.review-row:nth-child(2) .review-track { animation-direction: reverse; animation-duration: 42s; }
.review-row:nth-child(3) .review-track { animation-duration: 39s; }
/* 图片左侧间距为右侧的1.3倍，组尾留白保持一致以保证滚动衔接。 */
.review-group { display: flex; align-items: center; gap: 33.8px; padding-right: 33.8px; }
.review-item { display: flex; align-items: center; gap: 26px; }
.review-item img { width: 76px; height: 76px; object-fit: contain; }
.review-item p { display: flex; align-items: center; width: 900px; height: 68px; margin: 0; padding: 12px 30px; border: 1px solid #88abe6; border-radius: 3px; background: #fff; font-size: 20px; line-height: 1.6; white-space: nowrap; }
.review-marquee:hover .review-track, .review-marquee:focus-within .review-track { animation-play-state: paused; }
@keyframes reviews-scroll { to { transform: translateX(-50%); } }
/* 底部下载区使用独立切图，与固定首屏背景分别展示。 */
.download-banner { min-height: 314px; padding: 48px 24px 38px; text-align: center; background: url("dll/footer.png") center / cover no-repeat; color: #fff; }
.download-banner h2 { display: flex; align-items: center; justify-content: center; gap: 10px; margin: 0; font-size: 28px; font-weight: 500; }
.download-banner p { margin: 22px 0 34px; font-size: 20px; }
.download-banner .download-button { min-width: 200px; min-height: 60px; font-size: 18px; }
.download-banner .download-button svg { width: 20px; height: 20px; }
.download-banner .version { font-size: 13px; margin: 15px 0 0; }
.site-footer { display: flex; justify-content: center; flex-wrap: wrap; gap: 20px; padding: 16px 24px; font-size: 12px; color: #888; }
.site-footer button { border: 0; background: none; color: var(--blue); }
.download-status { position: fixed; z-index: 30; left: 50%; bottom: 24px; transform: translateX(-50%); max-width: calc(100% - 32px); width: max-content; padding: 14px 24px; background: #25364ef2; color: white; border-radius: 8px; font-size: 15px; box-shadow: 0 4px 20px #0002; }

@media (max-width: 1450px) {
    .repair-result { right: -15px; }
    .hero-copy { width: 46%; }
    h1 { font-size: 42px; }
    h1 small { font-size: 14px; padding: 4px 8px; }
    .hero-description { font-size: 22px; }
    .hero-visual { width: 53%; top: 135px; }
    .error-preview { width: 44%; top: 80%; left: -10%; }
    .steps-grid { gap: 45px; }
    .step { padding-inline: 16px; gap: 10px; }
    .step:not(:last-child)::after { right: -34px; }
    .step img { width: 60px; }
    nav { gap: 14px; font-size: 16px; }
}

@media (max-width: 1100px) {
    nav { display: none; }
    h1 { font-size: 34px; }
    h1 small { position: static; display: block; width: fit-content; margin-bottom: 12px; }
    .hero-description { font-size: 19px; }
    .hero-download, .system-note, .statistics { width: 100%; }
    .hero-download { max-width: 400px; }
    .hero-main { height: 620px; }
    .hero { min-height: auto; }
    .hero-visual { top: 180px; }
    .feature { width: 23%; }
    .feature img { max-width: 100%; }
    .section-title { font-size: 30px; gap: 24px; }
    .section-title::before, .section-title::after { width: 100px; }
    .steps-grid { gap: 24px; }
    .step { height: 160px; flex-wrap: wrap; }
    .step img { position: absolute; right: 12px; bottom: 10px; width: 45px; }
    .step:not(:last-child)::after { right: -22px; font-size: 26px; }
}

@media (max-width: 700px) {
    html { scroll-padding-top: 84px; }
    .container { width: calc(100% - 36px); }
    .site-header { height: 70px; }
    .header-inner { gap: 12px; }
    .brand { font-size: 18px; gap: 8px; letter-spacing: 0; }
    .brand img { width: 34px; height: 34px; }
    .brand small { font-size: 10px; }
    .header-inner > .download-button { font-size: 14px; padding: 7px 10px; gap: 5px; white-space: nowrap; }
    .header-inner > .download-button svg { width: 16px; height: 16px; }
    .hero-main { height: auto; }
    .hero-copy { width: 100%; padding-top: 48px; text-align: center; }
    h1 { font-size: clamp(28px, 7.8vw, 42px); }
    h1 small { font-size: 12px; line-height: 20px; margin: 8px auto 0; }
    .hero-description { margin: 20px 0 24px; font-size: 16px; line-height: 1.9; }
    .hero-download { max-width: 320px; height: 62px; font-size: 22px; }
    .system-note { margin-top: 10px; }
    .statistics { font-size: 17px; }
    .hero-visual { position: relative; top: auto; right: auto; width: calc(100% - 16px); margin: 72px 0 90px 8px; }
    .repair-result { width: 150px; height: 75px; top: -40px; right: -5px; padding: 12px 7px; }
    .repair-result > div { font-size: 13px; }
    .repair-result p { font-size: 9px; margin-top: 8px; }
    .checkmark { width: 20px; height: 20px; margin-right: 4px; }
    .error-preview { width: 48%; left: -4%; }
    .feature-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 32px 18px; padding: 0 0 50px; }
    .feature { width: 100%; }
    .feature-image { height: 115px; }
    .feature img { max-width: 150px; max-height: 110px; }
    .feature h2 { font-size: 20px; margin-top: 12px; }
    .feature p { font-size: 12px; }
    .section-title { font-size: 24px; gap: 12px; }
    .section-title::before, .section-title::after { width: 32px; }
    .section-description { margin: 16px 0 28px; font-size: 14px; line-height: 1.8; }
    .common-files { padding: 42px 0 22px; }
    .file-grid { grid-template-columns: 1fr; gap: 12px; }
    .file-card { height: 76px; }
    .file-card small { font-size: 12px; }
    .repair-steps { padding-top: 50px; padding-bottom: 20px; }
    .steps-grid { grid-template-columns: 1fr; margin-top: 30px; gap: 24px; }
    .step { height: 110px; gap: 16px; padding: 20px; flex-wrap: nowrap; }
    .step img { position: static; width: 70px; }
    .step p { font-size: 12px; }
    .step:not(:last-child)::after { right: 50%; top: 96px; transform: rotate(90deg); }
    .reviews { padding: 50px 0; }
    .reviews .section-description { font-size: 12px; margin: 15px 24px 30px; }
    .review-item { gap: 12px; }
    .review-item img { width: 48px; height: 48px; }
    .review-item p { width: 510px; height: 56px; font-size: 14px; padding-inline: 15px; }
    .review-group { gap: 15.6px; padding-right: 15.6px; }
    .review-row { margin-bottom: 14px; }
    .review-track { animation-duration: 30s; }
    .download-banner { min-height: 280px; padding: 40px 22px; }
    .download-banner h2 { font-size: 24px; }
    .download-banner p { font-size: 15px; line-height: 1.8; margin: 20px 0 28px; }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .review-track { animation: none; }
    .review-row { overflow-x: auto; }
    .review-marquee { mask-image: none; }
    .review-group[aria-hidden="true"] { display: none; }
}