/* ==========================================================================
   pap.er — “画廊与纸” Gallery & Paper redesign
   上半部：近黑画廊，壁纸是唯一的主角
   下半部：暖白纸面，衬线标题的编辑排版
   ========================================================================== */

:root {
    /* Gallery (dark) */
    --ink: #0b0c0f;
    --ink-soft: #121419;
    --gallery-text: #f3f1ec;
    --gallery-dim: rgba(243, 241, 236, 0.62);
    --gallery-faint: rgba(243, 241, 236, 0.38);
    --gallery-line: rgba(243, 241, 236, 0.14);

    /* Paper (light) */
    --paper: #f7f4ee;
    --paper-deep: #efeae0;
    --paper-ink: #1c1b18;
    --paper-dim: #6d6a62;
    --paper-line: rgba(28, 27, 24, 0.12);

    --serif: "Palatino", "Palatino Linotype", "Songti SC", "Noto Serif SC", "Hiragino Mincho ProN", Georgia, serif;
    --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Segoe UI", sans-serif;

    --brand-font: "Century Gothic", "Century Gothic Custom", sans-serif;

    --container: 1080px;
    --wide-gutter: clamp(24px, 7vw, 160px);
    --nav-h: 64px;
}

@font-face {
    font-family: "Century Gothic Custom";
    src: url("../font/cg.ttf") format("truetype");
    font-weight: normal;
    font-style: normal;
    font-display: swap;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--sans);
    background: var(--ink);
    color: var(--gallery-text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

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

a { color: inherit; }

.container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

.pap-er-brand {
    font-family: var(--brand-font);
    font-style: normal;
    letter-spacing: 0.02em;
}

/* --------------------------------------------------------------------------
   Section titles
   -------------------------------------------------------------------------- */
.section-title {
    font-family: var(--serif);
    font-weight: 500;
    font-size: clamp(1.7rem, 3.4vw, 2.4rem);
    letter-spacing: 0.02em;
    margin-bottom: 3rem;
    position: relative;
    padding-bottom: 1.1rem;
}

.section-title::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: 0;
    width: 3.5rem;
    height: 1px;
    background: currentColor;
    opacity: 0.4;
}

/* --------------------------------------------------------------------------
   Navbar — hairline glass over the gallery
   -------------------------------------------------------------------------- */
.navbar {
    position: fixed;
    inset: 0 0 auto 0;
    z-index: 100;
    height: var(--nav-h);
    background: transparent;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    border-bottom: 1px solid transparent;
}

.navbar .container {
    width: 100%;
    max-width: none;
    padding-right: var(--wide-gutter);
    padding-left: var(--wide-gutter);
    height: var(--nav-h);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo { width: 28px; height: 28px; border-radius: 7px; }

.brand-text {
    text-decoration: none;
    display: flex;
    align-items: baseline;
    gap: 10px;
}

.brand-text .pap-er-brand {
    font-size: 1.2rem;
    color: var(--gallery-text);
}

.brand-description {
    font-size: 0.78rem;
    letter-spacing: 0.22em;
    color: var(--gallery-faint);
    text-transform: uppercase;
}

.navbar-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.navbar-item {
    text-decoration: none;
    font-size: 0.88rem;
    letter-spacing: 0.04em;
    color: var(--gallery-dim);
    transition: color 0.25s ease;
    position: relative;
}

a.navbar-item::after {
    content: "";
    position: absolute;
    left: 0;
    right: 100%;
    bottom: -4px;
    height: 1px;
    background: var(--gallery-text);
    transition: right 0.3s ease;
}

a.navbar-item:hover { color: var(--gallery-text); }
a.navbar-item:hover::after { right: 0; }

/* Language selector */
.language-selector { position: relative; }

.current-language {
    display: flex;
    align-items: center;
    gap: 7px;
    background: none;
    border: 1px solid var(--gallery-line);
    border-radius: 999px;
    color: var(--gallery-dim);
    font: inherit;
    font-size: 0.82rem;
    padding: 5px 14px;
    cursor: pointer;
    transition: color 0.25s ease, border-color 0.25s ease;
}

.current-language:hover {
    color: var(--gallery-text);
    border-color: rgba(243, 241, 236, 0.4);
}

.globe-icon { width: 15px; height: 15px; }

.language-dropdown {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    min-width: 150px;
    background: rgba(18, 20, 25, 0.92);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    border: 1px solid var(--gallery-line);
    border-radius: 12px;
    padding: 6px;
    display: none;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.45);
}

.language-selector.open .language-dropdown { display: block; }

.language-dropdown a {
    display: block;
    padding: 8px 14px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 0.86rem;
    color: var(--gallery-dim);
    transition: background 0.2s ease, color 0.2s ease;
}

.language-dropdown a:hover {
    background: rgba(243, 241, 236, 0.08);
    color: var(--gallery-text);
}

/* Navbar themes — 滚动后显示玻璃底，进入暖白纸面时切换纸色 */
.navbar {
    transition: background 0.4s ease, border-color 0.4s ease,
                -webkit-backdrop-filter 0.4s ease, backdrop-filter 0.4s ease;
}

.navbar--scrolled {
    background: rgba(11, 12, 15, 0.55);
    -webkit-backdrop-filter: saturate(150%) blur(18px);
    backdrop-filter: saturate(150%) blur(18px);
    border-bottom-color: var(--gallery-line);
}

.navbar--paper {
    background: rgba(247, 244, 238, 0.72);
    -webkit-backdrop-filter: saturate(140%) blur(18px);
    backdrop-filter: saturate(140%) blur(18px);
    border-bottom-color: var(--paper-line);
}

.navbar--paper .brand-text .pap-er-brand { color: var(--paper-ink); }
.navbar--paper .brand-description { color: var(--paper-dim); }
.navbar--paper .navbar-item { color: var(--paper-dim); }
.navbar--paper a.navbar-item:hover { color: var(--paper-ink); }
.navbar--paper a.navbar-item::after { background: var(--paper-ink); }
.navbar--paper .current-language {
    color: var(--paper-dim);
    border-color: var(--paper-line);
}
.navbar--paper .current-language:hover {
    color: var(--paper-ink);
    border-color: rgba(28, 27, 24, 0.35);
}
.navbar--paper .navbar-toggle span { background: var(--paper-ink); }

/* Hamburger */
.navbar-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 40px;
    height: 40px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.navbar-toggle span {
    display: block;
    height: 1px;
    width: 100%;
    background: var(--gallery-text);
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.navbar-toggle.active span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.navbar-toggle.active span:nth-child(2) { opacity: 0; }
.navbar-toggle.active span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* --------------------------------------------------------------------------
   Hero — full-bleed wallpaper, the app's own subject matter
   -------------------------------------------------------------------------- */
.hero {
    position: relative;
    min-height: 100svh;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-backdrop {
    position: absolute;
    inset: 0;
    background: var(--ink);
    background-position: center;
    background-size: cover;
    background-repeat: no-repeat;
    opacity: 0;
    transition: opacity 0.55s ease;
}

.hero-backdrop.is-loaded { opacity: 1; }
.hero-backdrop.is-switching { opacity: 0; }

.hero-scrim {
    position: absolute;
    inset: 0;
    background:
        linear-gradient(to bottom, rgba(11, 12, 15, 0.55) 0%, rgba(11, 12, 15, 0.25) 40%, rgba(11, 12, 15, 0.88) 100%),
        radial-gradient(ellipse at 30% 80%, rgba(11, 12, 15, 0.55), transparent 60%);
}

.hero-content {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: none;
    margin: 0;
    padding-right: var(--wide-gutter);
    padding-left: var(--wide-gutter);
    padding-top: var(--nav-h);
    padding-bottom: 8vh;
}

.hero-kicker {
    font-size: 0.78rem;
    letter-spacing: 0.3em;
    /* 不用 uppercase：保持 macOS 品牌大小写 */
    color: var(--gallery-faint);
    margin-bottom: 1.6rem;
}

.hero h1 {
    font-family: var(--serif);
    font-weight: 500;
    font-size: clamp(2.3rem, 5.6vw, 4.2rem);
    line-height: 1.18;
    letter-spacing: 0.01em;
    max-width: 15em;
    text-wrap: balance;
    text-shadow: 0 2px 30px rgba(0, 0, 0, 0.35);
}

#app-description {
    margin-top: 1.4rem;
    font-size: clamp(1rem, 1.8vw, 1.2rem);
    color: var(--gallery-dim);
    max-width: 34em;
}

.hero-actions { margin-top: 2.8rem; }

.download-button {
    display: inline-block;
    transition: transform 0.25s ease, filter 0.25s ease;
}

.download-button:hover {
    transform: translateY(-2px);
    filter: brightness(1.1);
}

.download-links {
    margin-top: 1.1rem;
    font-size: 0.85rem;
    color: var(--gallery-faint);
}

.download-links a {
    color: var(--gallery-dim);
    text-decoration: none;
    border-bottom: 1px solid var(--gallery-line);
    padding-bottom: 1px;
    transition: color 0.25s ease, border-color 0.25s ease;
}

.download-links a:hover {
    color: var(--gallery-text);
    border-color: var(--gallery-dim);
}

.dot-sep { margin: 0 0.7em; }

.hero-scroll-hint {
    position: absolute;
    left: 50%;
    bottom: 26px;
    transform: translateX(-50%);
    z-index: 1;
}

.hero-scroll-hint span {
    display: block;
    width: 1px;
    height: 44px;
    background: linear-gradient(to bottom, transparent, var(--gallery-dim));
    animation: scroll-pulse 2.2s ease-in-out infinite;
}

.hero-rotation-control {
    --hero-duration: 12s;
    position: absolute;
    right: 30px;
    bottom: 25px;
    z-index: 2;
    width: 38px;
    height: 38px;
    padding: 0;
    border: 0;
    border-radius: 50%;
    color: var(--gallery-text);
    background: rgba(11, 12, 15, 0.28);
    cursor: pointer;
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    transition: background 0.25s ease, transform 0.25s ease;
}

.hero-rotation-control:hover {
    background: rgba(11, 12, 15, 0.52);
    transform: scale(1.06);
}

.hero-rotation-control:focus-visible {
    outline: 2px solid var(--gallery-text);
    outline-offset: 3px;
}

.hero-rotation-control svg {
    display: block;
    width: 100%;
    height: 100%;
}

.hero-rotation-track,
.hero-rotation-progress {
    fill: none;
    stroke-width: 1.1;
}

.hero-rotation-track { stroke: rgba(243, 241, 236, 0.2); }

.hero-rotation-progress {
    stroke: currentColor;
    stroke-dasharray: 100;
    stroke-dashoffset: 100;
    stroke-linecap: round;
    transform: rotate(-90deg);
    transform-origin: 18px 18px;
}

.hero-rotation-control.is-counting .hero-rotation-progress {
    animation: hero-countdown var(--hero-duration) linear forwards;
}

.hero-rotation-arrow {
    fill: none;
    stroke: currentColor;
    stroke-width: 1.3;
    stroke-linecap: round;
    stroke-linejoin: round;
}

@keyframes hero-countdown {
    to { stroke-dashoffset: 0; }
}

@keyframes scroll-pulse {
    0%, 100% { opacity: 0.25; transform: scaleY(0.7); transform-origin: top; }
    50%      { opacity: 1; transform: scaleY(1); transform-origin: top; }
}

/* --------------------------------------------------------------------------
   Screenshots — floating prints in the dark gallery
   -------------------------------------------------------------------------- */
.screenshots {
    background: var(--ink);
    padding: 4rem 0 2.5rem;
}

.swiper-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
    overflow: hidden;
    position: relative;
}

.swiper-slide img {
    width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.55);
    border: 1px solid var(--gallery-line);
    transition: transform 0.4s ease;
    background: var(--ink-soft) !important;
}

.swiper-slide:hover img { transform: translateY(-6px); }

.swiper-container .swiper-pagination,
.swiper-container > .swiper-pagination-bullets {
    position: static;
    margin-top: 2.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    text-align: center;
}

.swiper-container .swiper-pagination-bullet {
    position: relative;
    display: inline-block;
    width: 24px;
    height: 18px;
    margin: 0;
    padding: 0;
    border: 0;
    border-radius: 0;
    color: var(--gallery-text);
    background: transparent;
    opacity: 1;
    cursor: pointer;
    overflow: hidden;
    transition: width 0.35s ease;
}

.swiper-container .swiper-pagination-bullet::before,
.swiper-container .swiper-pagination-bullet::after {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 100%;
    height: 2px;
    border-radius: 999px;
    transform: translateY(-50%);
}

.swiper-container .swiper-pagination-bullet::before {
    background: rgba(243, 241, 236, 0.26);
    transition: background 0.25s ease;
}

.swiper-container .swiper-pagination-bullet:hover::before {
    background: rgba(243, 241, 236, 0.58);
}

.swiper-container .swiper-pagination-bullet:focus-visible {
    outline: 2px solid var(--gallery-text);
    outline-offset: 3px;
}

.swiper-container .swiper-pagination-bullet::after {
    background: var(--gallery-text);
    transform: translateY(-50%) scaleX(0);
    transform-origin: left;
}

.swiper-container .swiper-pagination-bullet-active {
    width: 64px;
}

.swiper-container .swiper-pagination-bullet-active::after {
    animation: screenshot-progress 3s linear forwards;
}

@keyframes screenshot-progress {
    from { transform: translateY(-50%) scaleX(0); }
    to { transform: translateY(-50%) scaleX(1); }
}

.noscript-warning { margin-bottom: 1.5rem; }

.alert-warning {
    border: 1px solid var(--gallery-line);
    border-radius: 8px;
    padding: 0.8rem 1.2rem;
    color: var(--gallery-dim);
    font-size: 0.85rem;
}

/* --------------------------------------------------------------------------
   Slogan — the turn of the page
   -------------------------------------------------------------------------- */
.brand-slogan {
    background: var(--ink);
    padding: 2rem 0 6rem;
    text-align: center;
}

/* 一条细竖线引入 slogan——暗转亮之前的“翻页”停顿 */
.brand-slogan .container::before {
    content: "";
    display: block;
    width: 1px;
    height: 3rem;
    margin: 0 auto 2rem;
    background: linear-gradient(to bottom, transparent, var(--gallery-dim));
}

.slogan-text {
    font-family: var(--serif);
    font-size: clamp(1.5rem, 3.6vw, 2.6rem);
    font-weight: 400;
    letter-spacing: 0.06em;
    line-height: 1.6;
    color: var(--gallery-text);
    display: inline-block;
    max-width: 22em;
    text-wrap: balance;
}

/* --------------------------------------------------------------------------
   Features — paper section, editorial numbered grid
   -------------------------------------------------------------------------- */
.features {
    background: var(--paper);
    color: var(--paper-ink);
    padding: 7rem 0;
    border-top: 1px solid var(--paper-line);
}

#app-features {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    border-top: 1px solid var(--paper-line);
    border-left: 1px solid var(--paper-line);
}

.feature-item {
    position: relative;
    padding: 2.6rem 2.4rem 2.8rem;
    border-right: 1px solid var(--paper-line);
    border-bottom: 1px solid var(--paper-line);
    transition: background 0.3s ease;
}

.feature-item:hover { background: var(--paper-deep); }

.feature-index {
    position: absolute;
    top: 1.4rem;
    right: 1.6rem;
    font-family: var(--serif);
    font-style: italic;
    font-size: 0.9rem;
    color: var(--paper-dim);
    opacity: 0.7;
}

.feature-icon-wrapper {
    position: relative;
    display: inline-flex;
    color: var(--paper-ink);
    margin-bottom: 1.4rem;
}

.icon-badge {
    position: absolute;
    top: -8px;
    right: -22px;
    font-size: 0.62rem;
    letter-spacing: 0.08em;
    border: 1px solid var(--paper-ink);
    border-radius: 999px;
    padding: 1px 7px;
    color: var(--paper-ink);
}

.feature-item h3 {
    font-family: var(--serif);
    font-weight: 600;
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    letter-spacing: 0.02em;
}

.feature-item p {
    color: var(--paper-dim);
    font-size: 0.95rem;
    max-width: 26em;
}

/* --------------------------------------------------------------------------
   Reviews — paper continues, quiet quotation cards
   -------------------------------------------------------------------------- */
.user-reviews {
    background: var(--paper);
    color: var(--paper-ink);
    padding: 6rem 0 7rem;
}

.reviews-container {
    columns: 2;
    column-gap: 1.5rem;
}

.review-item {
    break-inside: avoid;
    margin-bottom: 1.5rem;
    padding: 1.8rem 1.9rem;
    background: #fffdf9;
    border: 1px solid var(--paper-line);
    border-radius: 4px;
    box-shadow: 0 1px 2px rgba(28, 27, 24, 0.04);
}

.review-stars {
    color: #b98a2f;
    font-size: 0.8rem;
    letter-spacing: 0.25em;
    margin-bottom: 0.8rem;
}

.review-title {
    font-family: var(--serif);
    font-weight: 600;
    font-size: 1.05rem;
    margin-bottom: 0.5rem;
}

.review-text {
    font-size: 0.92rem;
    color: var(--paper-dim);
    margin-bottom: 0.9rem;
}

.review-author {
    font-family: var(--serif);
    font-style: italic;
    font-size: 0.85rem;
    color: var(--paper-dim);
    text-align: right;
}

/* --------------------------------------------------------------------------
   FAQ — back into the gallery dark
   -------------------------------------------------------------------------- */
.faq {
    background: var(--ink);
    color: var(--gallery-text);
    padding: 7rem 0;
}

.faq-list {
    border-top: 1px solid var(--gallery-line);
}

.faq-item {
    border-bottom: 1px solid var(--gallery-line);
}

.faq-question {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    padding: 1.4rem 0.2rem;
    cursor: pointer;
}

.faq-question:focus-visible {
    outline: 2px solid currentColor;
    outline-offset: 4px;
    border-radius: 2px;
}

.faq-question h3 {
    font-family: var(--serif);
    font-weight: 500;
    font-size: 1.08rem;
    letter-spacing: 0.02em;
    color: var(--gallery-dim);
    transition: color 0.25s ease;
}

.faq-item:hover .faq-question h3,
.faq-item.active .faq-question h3 { color: var(--gallery-text); }

.faq-toggle {
    position: relative;
    flex: 0 0 auto;
    width: 14px;
    height: 14px;
}

.faq-toggle::before,
.faq-toggle::after {
    content: "";
    position: absolute;
    background: var(--gallery-dim);
    transition: transform 0.3s ease;
}

.faq-toggle::before {
    left: 0; right: 0; top: 50%;
    height: 1px;
}

.faq-toggle::after {
    top: 0; bottom: 0; left: 50%;
    width: 1px;
}

.faq-item.active .faq-toggle::after { transform: scaleY(0); }

.faq-answer {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    padding: 0 1rem;
    transition: opacity 0.35s ease, padding 0.35s ease;
}

.faq-answer p {
    color: var(--gallery-dim);
    font-size: 0.94rem;
    max-width: 46em;
}

/* --------------------------------------------------------------------------
   Contact — a quiet closing plate
   -------------------------------------------------------------------------- */
.contact {
    background: var(--ink);
    padding: 3rem 0 8rem;
    text-align: center;
}

.contact .section-title {
    display: inline-block;
    padding-bottom: 1.1rem;
}

.contact .section-title::after {
    left: 50%;
    transform: translateX(-50%);
}

#contact-description {
    color: var(--gallery-dim);
    margin-bottom: 2.2rem;
}

.contact-button {
    display: inline-block;
    font-size: 0.9rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    text-decoration: none;
    color: var(--gallery-text);
    border: 1px solid rgba(243, 241, 236, 0.35);
    border-radius: 999px;
    padding: 0.85rem 2.6rem;
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.contact-button:hover {
    background: var(--gallery-text);
    color: var(--ink);
    border-color: var(--gallery-text);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.footer {
    background: var(--ink);
    border-top: 1px solid var(--gallery-line);
    padding: 2.2rem 0;
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}

.copyright {
    font-size: 0.85rem;
    color: var(--gallery-faint);
}

.footer-links {
    display: flex;
    gap: 1.8rem;
}

.footer-links a {
    font-size: 0.82rem;
    color: var(--gallery-faint);
    text-decoration: none;
    transition: color 0.25s ease;
}

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

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */
@media (max-width: 860px) {
    .navbar-toggle { display: flex; }

    .navbar-brand { flex: 1; justify-content: flex-start; }
    .navbar-brand .navbar-toggle { margin-left: auto; }

    .navbar-menu {
        position: fixed;
        top: var(--nav-h);
        left: 0;
        right: 0;
        flex-direction: column;
        align-items: flex-start;
        gap: 0;
        background: rgba(11, 12, 15, 0.96);
        -webkit-backdrop-filter: blur(24px);
        backdrop-filter: blur(24px);
        border-bottom: 1px solid var(--gallery-line);
        padding: 0.6rem 24px 1.2rem;
        display: none;
    }

    .navbar-menu.active { display: flex; }

    .navbar-menu .navbar-item {
        width: 100%;
        padding: 0.9rem 0;
        font-size: 1rem;
        border-bottom: 1px solid rgba(243, 241, 236, 0.07);
    }

    a.navbar-item::after { display: none; }

    .language-selector { border-bottom: none; padding-top: 1rem; }

    .language-dropdown {
        position: static;
        margin-top: 0.6rem;
        box-shadow: none;
    }

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

    .reviews-container { columns: 1; }

    .footer-content { justify-content: center; text-align: center; }
}

@media (min-width: 1600px) {
    .hero h1 {
        max-width: 14em;
        font-size: clamp(4.2rem, 3.5vw, 5.5rem);
    }

    #app-description { font-size: 1.3rem; }
}

@media (max-width: 480px) {
    .brand-description { display: none; }
    .hero-content { padding-bottom: 12vh; }
    .hero-rotation-control { right: 20px; bottom: 20px; }
    .screenshots { padding: 3rem 0 1.5rem; }
    .brand-slogan { padding: 1.5rem 0 4.5rem; }
    .feature-item { padding: 2.2rem 1.6rem 2.4rem; }
}

/* --------------------------------------------------------------------------
   Scroll reveal — body.js-reveal 由 enhancements.js 添加；
   无 JS 或 prefers-reduced-motion 时内容始终可见
   -------------------------------------------------------------------------- */
.js-reveal .feature-item,
.js-reveal .review-item,
.js-reveal .section-title,
.js-reveal .slogan-text,
.js-reveal .faq-item,
.js-reveal .contact-button,
.js-reveal #contact-description {
    opacity: 0;
    transform: translateY(18px);
    transition: opacity 0.7s ease, transform 0.7s ease,
                background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.js-reveal .is-revealed {
    opacity: 1;
    transform: none;
}

/* --------------------------------------------------------------------------
   Motion preferences
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .hero-backdrop { animation: none; transform: none; }
    .hero-scroll-hint span { animation: none; }
    * { transition-duration: 0.01ms !important; }
}