/* ========================================================================
   index.css —— YuanFit 官网主页(与 App 同风格:亮色 + 蓝紫柔彩)
   配色取自 App 首页:淡紫 #E9E3F7 → 淡薄荷 #E4F5EC 渐变底,
   主题蓝 #3392FF,辅助紫 #8E7BFF,白卡 85% 半透明 + 圆角 24 + 柔和阴影
   ======================================================================== */

:root {
    /* 配色(App 同款) */
    --bg-lavender: #E9E3F7;
    --bg-mint: #E4F5EC;
    --bg-card: rgba(255, 255, 255, 0.85);
    --bg-card-solid: #ffffff;
    --accent-blue: #3392FF;
    --accent-purple: #8E7BFF;
    --text-title: #22303F;
    --text-body: #3D4B5C;
    --text-sub: #6B7A90;
    --text-muted: #8A97A8;
    --border-soft: rgba(34, 48, 63, 0.08);
    --border-blue: rgba(51, 146, 255, 0.35);
    --gradient: linear-gradient(135deg, #3392FF 0%, #8E7BFF 100%);
    --gradient-soft: linear-gradient(135deg, rgba(51, 146, 255, 0.12) 0%, rgba(142, 123, 255, 0.12) 100%);
    --shadow-card: 0 4px 12px rgba(30, 41, 59, 0.06);
    --shadow-card-hover: 0 10px 28px rgba(51, 146, 255, 0.16);

    /* 字体 */
    --font-zh: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    --font-en: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

    /* 间距 */
    --max-width: 1200px;
    --header-height: 64px;
    --section-pad: 100px;
}

@media (max-width: 768px) {
    :root {
        --section-pad: 60px;
        --header-height: 56px;
    }
}

html,
body {
    /* App 首页同款:顶部淡紫 → 底部淡薄荷,长页面继续向浅延伸 */
    background: linear-gradient(180deg, var(--bg-lavender) 0%, var(--bg-mint) 55%, #ECF6F0 100%);
    background-attachment: fixed;
    color: var(--text-body);
    font-family: var(--font-zh), var(--font-en);
    font-size: 16px;
}

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

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
}

section {
    padding: var(--section-pad) 0;
    position: relative;
}

/* ========================================================================
   Header(白色玻璃态固定顶栏)
   ======================================================================== */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    z-index: 100;
    background: rgba(255, 255, 255, 0.75);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--border-soft);
}

.site-header__inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 20px;
    letter-spacing: 0.5px;
}

.brand__logo {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    object-fit: contain;
}

.brand__name {
    color: var(--text-title);
}

.nav {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav__link {
    color: var(--text-sub);
    font-size: 15px;
    transition: color 0.2s;
    position: relative;
}

.nav__link:hover,
.nav__link.is-active {
    color: var(--accent-blue);
}

.nav__link.is-active::after {
    content: "";
    position: absolute;
    bottom: -8px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient);
    border-radius: 2px;
}

.lang-switch {
    display: inline-flex;
    align-items: center;
    border: 1px solid var(--border-soft);
    border-radius: 999px;
    padding: 4px;
    background: rgba(255, 255, 255, 0.6);
}

.lang-switch__btn {
    padding: 4px 12px;
    font-size: 12px;
    color: var(--text-sub);
    border-radius: 999px;
    transition: color 0.2s, background-color 0.2s;
}

.lang-switch__btn.is-active {
    background: var(--gradient);
    color: #fff;
    font-weight: 600;
}

@media (max-width: 768px) {
    .nav {
        gap: 20px;
    }

    .nav__link {
        font-size: 14px;
    }
}

@media (max-width: 520px) {
    .brand__name {
        display: none;
    }
}

/* ========================================================================
   Hero(首屏)
   ======================================================================== */
.hero {
    min-height: 100vh;
    padding-top: calc(var(--header-height) + 60px);
    padding-bottom: 60px;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    /* 柔光:蓝 / 紫 光晕,呼应 App 淡彩渐变 */
    background:
        radial-gradient(ellipse 80% 60% at 50% -10%, rgba(51, 146, 255, 0.16), transparent 60%),
        radial-gradient(ellipse 60% 50% at 80% 80%, rgba(142, 123, 255, 0.14), transparent 60%),
        linear-gradient(180deg, var(--bg-lavender) 0%, var(--bg-mint) 100%);
}

.hero__inner {
    width: 100%;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hero__tag {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px;
    border: 1px solid var(--border-blue);
    border-radius: 999px;
    background: rgba(51, 146, 255, 0.08);
    color: var(--accent-blue);
    font-size: 13px;
    margin-bottom: 24px;
}

.hero__tag::before {
    content: "";
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent-blue);
    box-shadow: 0 0 12px rgba(51, 146, 255, 0.6);
}

.hero__title {
    font-size: clamp(40px, 7vw, 76px);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: 1px;
    margin-bottom: 20px;
    color: var(--text-title);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 14px 24px;
}

.hero__title-accent {
    background: var(--gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.hero__subtitle {
    font-size: clamp(15px, 2vw, 18px);
    color: var(--text-sub);
    max-width: 640px;
    margin-bottom: 36px;
    line-height: 1.8;
}

.hero__cta {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: 999px;
    font-size: 15px;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
}

/* 主按钮:App 同款蓝→紫渐变 + 白字 */
.btn--primary {
    background: var(--gradient);
    color: #fff;
    box-shadow: 0 8px 24px rgba(51, 146, 255, 0.35);
}

/* 次按钮:白底 + 蓝字描边 */
.btn--ghost {
    border: 1px solid var(--border-blue);
    color: var(--accent-blue);
    background: rgba(255, 255, 255, 0.8);
}

/* ========================================================================
   Section title(通用)
   ======================================================================== */
.section-head {
    text-align: center;
    margin-bottom: 56px;
}

.section-head__eyebrow {
    color: var(--accent-blue);
    font-size: 13px;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.section-head__title {
    font-size: clamp(28px, 4vw, 40px);
    font-weight: 700;
    color: var(--text-title);
    margin-bottom: 14px;
}

.section-head__subtitle {
    color: var(--text-sub);
    max-width: 620px;
    margin: 0 auto;
    font-size: 15px;
}

/* ========================================================================
   Features(核心功能)—— App 指标卡同款:白卡 85% + 圆角 24 + 白边 + 柔影
   ======================================================================== */
.features__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    padding: 36px 28px;
    background: var(--bg-card);
    border: 1px solid #ffffff;
    border-radius: 24px;
    box-shadow: var(--shadow-card);
    transition: transform 0.3s, box-shadow 0.3s, border-color 0.3s;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-card-hover);
}

.feature-card__icon {
    width: 56px;
    height: 56px;
    border-radius: 16px;
    background: var(--gradient-soft);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-blue);
    margin-bottom: 20px;
}

.feature-card__icon svg {
    width: 26px;
    height: 26px;
}

.feature-card__title {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-title);
    margin-bottom: 10px;
}

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

@media (max-width: 900px) {
    .features__grid {
        grid-template-columns: 1fr;
    }
}

/* ========================================================================
   Download CTA band(蓝紫渐变横幅 + 白底按钮)
   ======================================================================== */
.cta-band {
    padding: 80px 0;
}

.cta-band__inner {
    background: var(--gradient);
    border-radius: 28px;
    padding: 60px 40px;
    text-align: center;
    color: #fff;
    position: relative;
    overflow: hidden;
    box-shadow: 0 16px 40px rgba(51, 146, 255, 0.3);
}

.cta-band__title {
    font-size: clamp(26px, 4vw, 36px);
    font-weight: 800;
    margin-bottom: 12px;
}

.cta-band__desc {
    font-size: 15px;
    margin-bottom: 28px;
    opacity: 0.9;
}

.cta-band__btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    background: #fff;
    color: var(--accent-blue);
    border-radius: 999px;
    font-weight: 600;
    box-shadow: 0 6px 18px rgba(30, 41, 59, 0.15);
    transition: transform 0.2s;
}

.cta-band__btn:hover {
    transform: translateY(-2px);
}

@media (max-width: 768px) {
    .cta-band__inner {
        padding: 40px 20px;
    }
}

/* ========================================================================
   Footer
   ======================================================================== */
.site-footer {
    border-top: 1px solid var(--border-soft);
    padding: 56px 0 32px;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.footer__grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer__brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
    font-weight: 700;
    color: var(--text-title);
    margin-bottom: 14px;
}

.footer__brand img {
    width: 28px;
    height: 28px;
    border-radius: 6px;
}

.footer__about {
    color: var(--text-sub);
    font-size: 14px;
    line-height: 1.7;
    max-width: 360px;
}

.footer__col-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-title);
    margin-bottom: 14px;
}

.footer__col-item {
    color: var(--text-sub);
    font-size: 14px;
    line-height: 2;
}

.footer__bottom {
    border-top: 1px solid var(--border-soft);
    padding-top: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-muted);
    font-size: 13px;
    flex-wrap: wrap;
    gap: 8px;
}

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

@media (max-width: 768px) {
    .footer__grid {
        grid-template-columns: 1fr;
        gap: 28px;
    }

    .footer__bottom {
        flex-direction: column;
        text-align: center;
    }
}