:root {
    --paper: #f8fafc;
    --paper-strong: #ffffff;
    --paper-muted: #eef3f6;
    --ink: #0f172a;
    --ink-soft: #1d2a3d;
    --slate: #5b6b80;
    --slate-light: #9fa7b2;
    --line: rgba(15, 23, 42, 0.12);
    --line-strong: rgba(15, 23, 42, 0.22);
    --dark: #0b1014;
    --dark-soft: #11181e;
    --dark-panel: rgba(17, 24, 30, 0.88);
    --dark-line: rgba(159, 167, 178, 0.19);
    --cyan: #67d0e2;
    --cyan-deep: #1f7d91;
    --teal: #08766f;
    --amber: #ffbe55;
    --amber-soft: #f2d06b;
    --danger: #e38a94;
    --success: #78c9a6;
    --font-sans: "IBM Plex Sans", "Segoe UI", sans-serif;
    --font-display: "Anta", "IBM Plex Sans", sans-serif;
    --font-mono: "IBM Plex Mono", "SFMono-Regular", monospace;
    --container: 1280px;
    --header-height: 76px;
    --radius-sm: 4px;
    --radius-md: 8px;
    --shadow-sm: 0 14px 35px rgba(15, 23, 42, 0.08);
    --shadow-dark: 0 28px 80px rgba(0, 0, 0, 0.28);
}

html[lang^="zh"] {
    --font-sans: "Noto Sans SC", "Microsoft YaHei", sans-serif;
}

html[lang^="zh"] h1,
html[lang^="zh"] h2,
html[lang^="zh"] h3 {
    font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif;
    letter-spacing: -0.02em;
}

html[lang^="zh"] .hero-copy h1 {
    font-size: clamp(3rem, 4.2vw, 3.75rem);
    line-height: 1.15;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-height) + 18px);
}

body {
    position: relative;
    margin: 0;
    min-width: 320px;
    background: var(--paper);
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    isolation: isolate;
}

.global-field-canvas {
    position: fixed;
    inset: 0;
    z-index: 0;
    width: 100vw;
    height: 100vh;
    max-width: none;
    pointer-events: none;
    background: var(--dark);
}

main,
.site-footer {
    position: relative;
    z-index: 1;
}

body.menu-open {
    overflow: hidden;
}

body.contact-open {
    overflow: hidden;
}

button,
input,
textarea,
select {
    font: inherit;
}

button,
a {
    -webkit-tap-highlight-color: transparent;
}

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

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

h1,
h2,
h3,
p,
blockquote,
ol,
ul {
    margin-top: 0;
}

h1,
h2,
h3 {
    margin-bottom: 0;
    font-weight: 600;
    letter-spacing: -0.035em;
    line-height: 1.08;
}

p:last-child,
ol:last-child,
ul:last-child {
    margin-bottom: 0;
}

.skip-link {
    position: fixed;
    top: 10px;
    left: 10px;
    z-index: 1000;
    padding: 0.65rem 0.85rem;
    color: #fff;
    background: var(--ink);
    border-radius: var(--radius-sm);
    transform: translateY(-160%);
}

.skip-link:focus {
    transform: translateY(0);
}

:focus-visible {
    outline: 3px solid rgba(31, 125, 145, 0.42);
    outline-offset: 3px;
}

.site-container {
    width: min(calc(100% - 48px), var(--container));
    margin-inline: auto;
}

.site-header {
    position: fixed;
    inset: 0 0 auto;
    z-index: 100;
    min-height: var(--header-height);
    background: rgba(248, 250, 252, 0.86);
    border-bottom: 1px solid var(--line);
    backdrop-filter: blur(18px) saturate(150%);
    transition: background-color 180ms ease, box-shadow 180ms ease;
}

.site-header.is-scrolled {
    background: rgba(248, 250, 252, 0.96);
    box-shadow: 0 8px 30px rgba(15, 23, 42, 0.06);
}

.nav-shell {
    min-height: var(--header-height);
    display: flex;
    align-items: center;
    gap: 2rem;
}

.brand {
    display: inline-flex;
    flex: 0 0 auto;
    align-items: center;
    gap: 0.72rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.brand-mark {
    width: 25px;
    height: 25px;
}

.brand-name {
    font-size: 1.06rem;
}

.desktop-nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: clamp(1rem, 2vw, 2rem);
    margin-inline: auto;
}

.desktop-nav a,
.site-footer nav a {
    color: var(--slate);
    font-size: 0.86rem;
    font-weight: 500;
    transition: color 150ms ease;
}

.desktop-nav a:hover,
.site-footer nav a:hover {
    color: var(--ink);
}

.nav-actions {
    display: flex;
    flex: 0 0 auto;
    align-items: center;
    gap: 0.75rem;
}

.language-menu {
    position: relative;
    z-index: 2;
    display: inline-grid;
    flex: 0 0 auto;
}

.language-toggle,
.language-options [data-language-option] {
    color: var(--ink-soft);
    font-family: var(--font-mono);
    font-size: 0.68rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    cursor: pointer;
}

.language-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.48rem;
    width: 54px;
    min-height: 40px;
    padding: 0.45rem 0.55rem;
    background: rgba(255, 255, 255, 0.76);
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    backdrop-filter: blur(12px);
    transition: color 180ms ease, background-color 180ms ease, border-color 180ms ease, box-shadow 220ms ease;
}

.language-toggle:hover,
.language-menu.is-open .language-toggle {
    color: var(--teal);
    background: #fff;
    border-color: rgba(8, 118, 111, 0.28);
    box-shadow: 0 9px 24px rgba(15, 23, 42, 0.09);
}

.language-toggle svg {
    width: 9px;
    height: 6px;
    transition: transform 260ms var(--motion-ease, ease);
}

.language-menu.is-open .language-toggle svg {
    transform: rotate(180deg);
}

.language-options {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    display: grid;
    width: 54px;
    padding: 4px;
    background: rgba(255, 255, 255, 0.94);
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    box-shadow: 0 18px 44px rgba(15, 23, 42, 0.14);
    backdrop-filter: blur(18px) saturate(150%);
    opacity: 0;
    visibility: hidden;
    transform: translate3d(0, -7px, 0) scale(0.97);
    transform-origin: top right;
    pointer-events: none;
    transition:
        opacity 180ms ease,
        transform 240ms var(--motion-ease, ease),
        visibility 0s linear 240ms;
}

.language-menu.is-open .language-options {
    opacity: 1;
    visibility: visible;
    transform: translate3d(0, 0, 0) scale(1);
    pointer-events: auto;
    transition-delay: 0s;
}

.language-options [data-language-option] {
    position: relative;
    display: grid;
    place-items: center;
    min-height: 38px;
    padding: 0.45rem;
    background: transparent;
    border: 0;
    border-radius: 2px;
    opacity: 0;
    transform: translateY(-5px);
    transition: color 160ms ease, background-color 160ms ease, opacity 220ms ease, transform 240ms var(--motion-ease, ease);
    transition-delay: calc(var(--option-index) * 28ms);
}

.language-menu.is-open .language-options [data-language-option] {
    opacity: 1;
    transform: translateY(0);
}

.language-options [data-language-option]:hover {
    color: var(--teal);
    background: rgba(8, 118, 111, 0.07);
}

.language-options [data-language-option][aria-selected="true"] {
    color: #fff;
    background: var(--ink);
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0.78rem 1.2rem;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    font-weight: 600;
    line-height: 1.2;
    text-align: center;
    transition: transform 160ms ease, background-color 160ms ease, border-color 160ms ease, box-shadow 160ms ease;
}

.button:hover {
    transform: translateY(-1px);
}

.button-small {
    min-height: 40px;
    padding: 0.62rem 0.92rem;
    font-size: 0.78rem;
}

.button-primary,
.button-ink {
    color: #fff;
    background: var(--ink);
    box-shadow: 0 10px 25px rgba(15, 23, 42, 0.14);
}

.button-primary:hover,
.button-ink:hover {
    background: var(--ink-soft);
    box-shadow: 0 14px 30px rgba(15, 23, 42, 0.19);
}

.button-light {
    color: var(--ink);
    background: #fff;
    box-shadow: 0 14px 36px rgba(0, 0, 0, 0.2);
}

.button-light:hover {
    background: var(--paper);
}

.text-link {
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    color: var(--ink);
    font-size: 0.9rem;
    font-weight: 600;
}

.text-link span {
    color: var(--teal);
    transition: transform 160ms ease;
}

.text-link:hover span {
    transform: translateX(3px);
}

.menu-toggle {
    display: none;
    width: 44px;
    height: 44px;
    padding: 0;
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    background: rgba(255, 255, 255, 0.78);
    cursor: pointer;
}

.menu-toggle span {
    display: block;
    width: 17px;
    height: 1.5px;
    margin: 5px auto;
    background: var(--ink);
    transition: transform 160ms ease;
}

.menu-toggle[aria-expanded="true"] span:first-child {
    transform: translateY(3.25px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:last-child {
    transform: translateY(-3.25px) rotate(-45deg);
}

.mobile-nav {
    position: fixed;
    inset: var(--header-height) 0 auto;
    display: grid;
    padding: 1rem 24px 1.5rem;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
}

.mobile-nav[hidden] {
    display: none;
}

.mobile-nav a {
    padding: 0.85rem 0;
    border-bottom: 1px solid var(--line);
    font-size: 0.96rem;
    font-weight: 600;
}

.mobile-nav a:last-child {
    color: var(--teal);
    border-bottom: 0;
}

.section-light,
.section-muted,
.section-dark,
.section-ink {
    position: relative;
    overflow: hidden;
}

.section-light {
    background: var(--paper);
}

.section-muted {
    background: var(--paper-muted);
}

.section-dark {
    color: #f5f6f8;
    background: rgba(11, 16, 20, 0.58);
}

.section-ink {
    color: #f5f6f8;
    background: linear-gradient(145deg, rgba(17, 26, 33, 0.78), rgba(12, 18, 23, 0.58) 65%);
}

.eyebrow {
    margin-bottom: 1rem;
    color: var(--teal);
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.17em;
    line-height: 1.35;
    text-transform: uppercase;
}

.eyebrow-dark {
    color: var(--cyan);
}

.section-heading h2 {
    max-width: 830px;
    font-size: clamp(2.15rem, 4.6vw, 4.15rem);
}

.split-heading {
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(280px, 0.58fr);
    gap: clamp(2rem, 7vw, 7rem);
    align-items: end;
}

.split-heading > p {
    margin-bottom: 0.25rem;
    color: var(--slate);
    font-size: 1.05rem;
    line-height: 1.75;
}

.split-heading-dark > p {
    color: var(--slate-light);
}

.centered-heading {
    max-width: 820px;
    margin-inline: auto;
    text-align: center;
}

.system-label {
    display: block;
    color: var(--cyan);
    font-family: var(--font-mono);
    font-size: 0.66rem;
    font-weight: 600;
    letter-spacing: 0.2em;
    text-transform: uppercase;
}

.window-dots {
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.window-dots i {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--amber);
}

.window-dots i:nth-child(2) {
    background: var(--cyan);
}

.window-dots i:nth-child(3) {
    background: var(--slate-light);
}

.field-canvas {
    pointer-events: none;
}

.field-canvas-full {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
}

.site-footer {
    color: var(--slate-light);
    background: rgba(8, 12, 16, 0.84);
    border-top: 1px solid var(--dark-line);
    backdrop-filter: blur(3px);
}

.footer-main {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 2rem;
    padding-block: 3rem;
}

.brand-footer {
    color: #f5f6f8;
}

.footer-main > div > p {
    margin: 0.9rem 0 0;
    font-size: 0.88rem;
}

.site-footer nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 1rem 1.6rem;
}

.site-footer nav a:hover {
    color: #fff;
}

.site-footer nav a {
    color: var(--slate-light);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    gap: 2rem;
    padding-block: 1.4rem 2.1rem;
    border-top: 1px solid var(--dark-line);
    font-family: var(--font-mono);
    font-size: 0.68rem;
}

.footer-bottom p {
    margin: 0;
}

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

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}