/* =====================================================================
   lt · 浅色版骨架
   ---------------------------------------------------------------------
   命名空间统一用 lt-，与深色版 v4 / v4- 完全隔离，两套样式可以并存，
   首页只加载 lt.css + home-lt.css，内页继续用 v4.css 的深色导航。
   ===================================================================== */

/* =====================================================================
   lt · 主题令牌（默认浅色）
   ---------------------------------------------------------------------
   所有颜色都收敛到这里的语义变量。lt-dark.css 只要覆盖这一组变量，
   就能把整站切换成深色，不需要改任何一条结构样式。
   ===================================================================== */

:root {
    /* 底色与表面 */
    --lt-paper: #fcfcfe;
    --lt-paper-2: #f6f7fb;
    --lt-surface: #ffffff;
    --lt-media: #eef0f8;

    /* 文字 */
    --lt-ink: #0f1222;
    --lt-ink-2: #2a2e45;
    --lt-muted: #6e7390;
    --lt-muted-2: #9297ad;
    --lt-faint: #b6b9c9;

    /* 分隔线 */
    --lt-line: #e9eaf2;
    --lt-line-soft: #f2f3f8;
    --lt-line-2: rgba(15, 18, 34, .2);
    --lt-dash: #d9dbe8;

    /* 强调色 */
    --lt-indigo: #4f46e5;
    --lt-violet: #7c3aed;
    --lt-sky: #0284c7;
    --lt-rose: #e2568f;

    /* 需要压白字的深色渐变（品牌标、主按钮、贴纸） */
    --lt-grad-btn: linear-gradient(100deg, #4f46e5 0%, #7c3aed 48%, #0284c7 100%);
    /* 用于文字的亮渐变（标题、引用强调） */
    --lt-grad: linear-gradient(100deg, #4f46e5 0%, #7c3aed 48%, #0284c7 100%);

    /* 主按钮 */
    --lt-btn-bg: #0f1222;
    --lt-btn-fg: #ffffff;
    --lt-btn-bg-hover: #1a1e34;

    /* 色块与半透明层 */
    --lt-tint-indigo: #eef0ff;
    --lt-tint-sky: #eaf6ff;
    --lt-tint-rose: #fff0f6;
    --lt-glass: rgba(252, 252, 254, .78);
    --lt-glass-strong: rgba(255, 255, 255, .9);
    --lt-chip: rgba(255, 255, 255, .94);
    --lt-panel: rgba(255, 255, 255, .72);
    --lt-dot: rgba(15, 18, 34, .13);
    --lt-band: linear-gradient(180deg, #f7f6ff 0%, #fbfaff 100%);
    --lt-card-wash:
        radial-gradient(80% 120% at 92% 0%, rgba(124, 58, 237, .13), transparent 58%),
        radial-gradient(70% 120% at 0% 100%, rgba(2, 132, 199, .10), transparent 58%),
        #ffffff;

    /* 阴影 */
    --lt-shadow-sm: 0 1px 2px rgba(15, 18, 34, .04), 0 4px 10px -6px rgba(15, 18, 34, .10);
    --lt-shadow: 0 18px 44px -28px rgba(15, 18, 34, .28);
    --lt-shadow-lg: 0 44px 90px -46px rgba(64, 54, 160, .42);

    --lt-rad: 20px;
    --lt-nav-h: 72px;
    --lt-pad: clamp(18px, 4.6vw, 56px);
    --lt-max: 1200px;
    --lt-ease: cubic-bezier(.22, .61, .36, 1);
}

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

html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--lt-nav-h) + 14px);
}

body {
    margin: 0;
    background: var(--lt-paper);
    color: var(--lt-ink);
    font-family: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Hiragino Sans GB",
        system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
    font-size: 16px;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    overflow-x: hidden;
}

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

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

button {
    font: inherit;
    color: inherit;
    background: none;
    border: 0;
    cursor: pointer;
}

:where(a, button, [tabindex]):focus-visible {
    outline: 2px solid var(--lt-indigo);
    outline-offset: 3px;
    border-radius: 8px;
}

.lt-wrap {
    width: 100%;
    max-width: var(--lt-max);
    margin-inline: auto;
    padding-inline: var(--lt-pad);
    min-width: 0;
}

.lt-sr {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
}

/* ===================== 导航 ===================== */

.lt-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: var(--lt-glass);
    -webkit-backdrop-filter: blur(16px) saturate(160%);
    backdrop-filter: blur(16px) saturate(160%);
    transition: background .3s var(--lt-ease), box-shadow .3s var(--lt-ease),
        border-color .3s var(--lt-ease);
    border-bottom: 1px solid transparent;
}

.lt-nav.is-stuck {
    background: var(--lt-glass-strong);
    border-bottom-color: var(--lt-line);
    box-shadow: 0 1px 2px rgba(15, 18, 34, .04);
}

.lt-nav__inner {
    display: flex;
    align-items: center;
    gap: 14px;
    height: var(--lt-nav-h);
}

.lt-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 0;
    flex: 0 1 auto;
}

.lt-brand__mark {
    flex: 0 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 3px;
    width: 34px;
    height: 34px;
    border-radius: 10px;
    background: var(--lt-grad-btn);
    box-shadow: 0 6px 14px -8px rgba(79, 70, 229, .9);
}

.lt-brand__mark i {
    display: block;
    width: 4px;
    height: 15px;
    border-radius: 2px;
    background: var(--lt-surface);
    transform: skewX(-14deg);
    opacity: .95;
}

.lt-brand__mark i:nth-child(2) { opacity: .78; }
.lt-brand__mark i:nth-child(3) { opacity: .6; }

.lt-brand__logo {
    flex: 0 0 auto;
    width: 34px;
    height: 34px;
    object-fit: contain;
    border-radius: 9px;
}

.lt-brand__text {
    display: flex;
    flex-direction: column;
    line-height: 1.15;
    min-width: 0;
}

.lt-brand__text strong {
    font-size: 15px;
    font-weight: 800;
    letter-spacing: -.01em;
    color: var(--lt-ink);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.lt-brand__text small {
    font-size: 8.5px;
    letter-spacing: .18em;
    text-transform: uppercase;
    color: var(--lt-muted);
    white-space: nowrap;
}

.lt-nav__links {
    display: none;
    align-items: center;
    gap: 2px;
    margin-left: auto;
}

.lt-nav__link {
    position: relative;
    padding: 9px 13px;
    font-size: 14px;
    font-weight: 600;
    color: var(--lt-ink-2);
    border-radius: 10px;
    transition: color .2s var(--lt-ease), background .2s var(--lt-ease);
}

.lt-nav__link:hover {
    color: var(--lt-indigo);
    background: rgba(79, 70, 229, .06);
}

.lt-nav__link.is-active { color: var(--lt-indigo); }

.lt-nav__link.is-active::after {
    content: "";
    position: absolute;
    left: 13px;
    right: 13px;
    bottom: 2px;
    height: 2px;
    border-radius: 2px;
    background: var(--lt-grad);
}

.lt-nav__cta {
    display: none;
    align-items: center;
    gap: 6px;
    margin-left: 10px;
    padding: 10px 18px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 700;
    color: var(--lt-btn-fg);
    background: var(--lt-btn-bg);
    white-space: nowrap;
    box-shadow: 0 10px 22px -14px rgba(15, 18, 34, .9);
    transition: transform .25s var(--lt-ease), box-shadow .25s var(--lt-ease);
}

.lt-nav__cta:hover {
    transform: translateY(-1px);
    box-shadow: 0 14px 26px -14px rgba(15, 18, 34, .9);
}

.lt-burger {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    width: 44px;
    height: 44px;
    margin-left: auto;
    border-radius: 12px;
    border: 1px solid var(--lt-line);
    background: var(--lt-surface);
    box-shadow: var(--lt-shadow-sm);
}

.lt-burger span {
    display: block;
    width: 18px;
    height: 2px;
    border-radius: 2px;
    background: var(--lt-ink);
    transition: transform .28s var(--lt-ease), opacity .2s var(--lt-ease);
}

.lt-burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.lt-burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.lt-burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@media (min-width: 960px) {
    .lt-nav__links { display: flex; }
    .lt-nav__cta { display: inline-flex; }
    .lt-burger { display: none; }
}

/* 移动端抽屉 */

.lt-drawer {
    position: fixed;
    inset: 0;
    z-index: 99;
    display: flex;
    flex-direction: column;
    padding: calc(var(--lt-nav-h) + 12px) var(--lt-pad) 32px;
    background: var(--lt-glass-strong);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-12px);
    transition: opacity .28s var(--lt-ease), transform .28s var(--lt-ease), visibility .28s;
    overflow-y: auto;
}

.lt-drawer.is-open {
    visibility: visible;
    opacity: 1;
    transform: none;
}

.lt-drawer__link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 17px 2px;
    font-size: 19px;
    font-weight: 700;
    color: var(--lt-ink);
    border-bottom: 1px solid var(--lt-line);
}

.lt-drawer__link small {
    font-size: 10px;
    letter-spacing: .18em;
    text-transform: uppercase;
    color: var(--lt-muted);
    font-weight: 600;
}

.lt-drawer__cta {
    margin-top: 26px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
    border-radius: 14px;
    font-size: 15px;
    font-weight: 700;
    color: var(--lt-btn-fg);
    background: var(--lt-btn-bg);
}

@media (min-width: 960px) {
    .lt-drawer { display: none; }
}

/* ===================== 按钮 ===================== */

.lt-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 9px;
    min-height: 52px;
    padding: 0 26px;
    border-radius: 999px;
    font-size: 15px;
    font-weight: 700;
    letter-spacing: .01em;
    white-space: nowrap;
    transition: transform .25s var(--lt-ease), box-shadow .25s var(--lt-ease),
        background .25s var(--lt-ease), border-color .25s var(--lt-ease), color .25s var(--lt-ease);
}

.lt-btn b { font-weight: 700; }

.lt-btn--ink {
    color: var(--lt-btn-fg);
    background: var(--lt-btn-bg);
    box-shadow: 0 16px 30px -18px rgba(15, 18, 34, .95);
}

.lt-btn--ink:hover {
    transform: translateY(-2px);
    background: var(--lt-btn-bg-hover);
    box-shadow: 0 20px 36px -18px rgba(15, 18, 34, .9);
}

.lt-btn--line {
    color: var(--lt-ink);
    background: var(--lt-surface);
    border: 1px solid var(--lt-line);
    box-shadow: var(--lt-shadow-sm);
}

.lt-btn--line:hover {
    transform: translateY(-2px);
    border-color: rgba(79, 70, 229, .45);
    color: var(--lt-indigo);
}

.lt-btn--grad {
    color: #fff;
    background: var(--lt-grad-btn);
    box-shadow: 0 18px 34px -20px rgba(79, 70, 229, .95);
}

.lt-btn--grad:hover {
    transform: translateY(-2px);
    box-shadow: 0 24px 44px -20px rgba(79, 70, 229, .9);
}

/* ===================== 页脚 ===================== */

/* ===================== 通用小部件 ===================== */

/* 页面眉标（首页与内页共用） */
.lt-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px 6px 11px;
    border: 1px solid var(--lt-line);
    border-radius: 999px;
    background: var(--lt-surface);
    box-shadow: var(--lt-shadow-sm);
    font-size: 10.5px;
    font-weight: 600;
    letter-spacing: .16em;
    text-transform: uppercase;
    color: var(--lt-muted);
    white-space: nowrap;
}

.lt-eyebrow i {
    width: 6px;
    height: 6px;
    flex: none;
    border-radius: 50%;
    background: var(--lt-indigo);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, .12);
}

.lt-eyebrow b { color: var(--lt-ink-2); font-weight: 700; }

@media (max-width: 359px) {
    .lt-eyebrow { font-size: 9px; letter-spacing: .1em; gap: 6px; }
}

/* ===================== 页脚 ===================== */

.lt-foot {
    background: var(--lt-paper-2);
    border-top: 1px solid var(--lt-line);
    padding-block: clamp(40px, 6vw, 68px) 26px;
}

.lt-foot__grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 32px;
}

@media (min-width: 820px) {
    .lt-foot__grid {
        grid-template-columns: minmax(0, 1.35fr) minmax(0, .65fr) minmax(0, 1fr);
        gap: 48px;
        align-items: start;
    }
}

.lt-foot__brand {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 13px;
}

.lt-foot__brand-name {
    display: flex;
    align-items: center;
    gap: 10px;
}

.lt-foot__brand-name strong {
    font-size: 16px;
    font-weight: 800;
    color: var(--lt-ink);
}

.lt-foot__brand p {
    margin: 0;
    max-width: 26em;
    font-size: 13.5px;
    line-height: 1.8;
    color: var(--lt-muted);
}

.lt-foot__title {
    margin: 0 0 14px;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: .22em;
    text-transform: uppercase;
    color: var(--lt-muted-2);
}

.lt-foot__links {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, auto));
    justify-content: start;
    gap: 10px 26px;
}

.lt-foot__links a {
    font-size: 14px;
    color: var(--lt-ink-2);
    transition: color .2s var(--lt-ease);
}

.lt-foot__links a:hover { color: var(--lt-indigo); }

.lt-foot__contact { display: flex; flex-direction: column; gap: 8px; }

.lt-foot__contact a {
    font-size: 15px;
    font-weight: 700;
    color: var(--lt-ink);
    word-break: break-all;
    transition: color .2s var(--lt-ease);
}

.lt-foot__contact a:hover { color: var(--lt-indigo); }

.lt-foot__contact p {
    margin: 0;
    font-size: 13px;
    color: var(--lt-muted);
}

/* 备案信息整行居中 */
.lt-foot__legal {
    margin-top: 34px;
    padding-top: 20px;
    border-top: 1px solid var(--lt-line);
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 10px 20px;
    font-size: 12px;
    text-align: center;
    color: var(--lt-muted);
}

.lt-foot__legal a { color: var(--lt-muted); transition: color .2s var(--lt-ease); }
.lt-foot__legal a:hover { color: var(--lt-ink); }

.lt-foot__police {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.lt-foot__police img { width: 16px; height: 18px; flex: none; }