:root {
    --bg: #f6f7f9;
    --surface: #ffffff;
    --text: #1a1f27;
    --muted: #5c6570;
    --accent: #134e6f;
    --accent-hover: #0e3d59;
    --border: #d9dde3;
    --title-font: "Noto Serif SC", "Source Han Serif SC", serif;
    --body-font: "Noto Sans SC", "PingFang SC", sans-serif;
    --hero-size: clamp(2.2rem, 4vw, 3.6rem);
    --body-size: 15px;
    --title-weight: 700;
    --card-radius: 6px;
    --button-radius: 4px;
    --border-width: 1px;
    --section-gap: clamp(44px, 6vw, 72px);
    --card-padding: clamp(18px, 2.5vw, 28px);
    --cluster-gap: clamp(14px, 1.8vw, 22px);
    --fast: 120ms;
    --normal: 200ms;
    --ease: ease;
    --container: min(1120px, calc(100vw - 32px));
    --header-bg: #1a1f27;
    --header-text: #f6f7f9;
    --header-muted: #a7aeb8;
    --nav-active-bg: rgba(255, 255, 255, 0.1);
    --footer-bg: #1a1f27;
    --footer-text: #f6f7f9;
    --footer-muted: #a7aeb8;
    --footer-border: #2c333d;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--body-font);
    font-size: var(--body-size);
    line-height: 1.7;
}

a {
    color: inherit;
    text-decoration: none;
    transition: color var(--fast) var(--ease), background var(--fast) var(--ease);
}

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

.container {
    width: var(--container);
    margin: 0 auto;
}

header,
.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: var(--header-bg);
    border-bottom: 1px solid var(--footer-border);
}

header .container,
.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    min-height: 64px;
}

.logo h1 {
    margin: 0;
    color: var(--header-text);
    font-family: var(--title-font);
    font-size: 1.25rem;
    font-weight: var(--title-weight);
    letter-spacing: 0.02em;
}

nav ul {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 0;
    margin: 0;
    list-style: none;
}

nav a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 36px;
    padding: 0 16px;
    border-radius: var(--button-radius);
    color: var(--header-muted);
    font-size: 0.95rem;
}

nav a.active,
nav a:hover {
    color: var(--header-text);
    background: var(--nav-active-bg);
}

.mobile-menu-btn {
    display: none;
    color: var(--header-text);
}

.hero,
.page-hero,
.about-preview,
.polish-section,
.about-shell {
    padding: var(--section-gap) 0;
}

.hero {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}

.page-hero {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}

.hero-grid {
    display: grid;
    gap: clamp(24px, 4vw, 48px);
    align-items: stretch;
}

.hero-grid-single {
    grid-template-columns: minmax(0, 1fr);
}

.hero-copy,
.about-content,
.narrative-panel,
.company-narrative,
.page-hero .container,
.footer-content {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--card-radius);
}

.hero-copy,
.narrative-panel,
.company-narrative,
.page-hero .container,
.footer-content {
    padding: var(--card-padding);
}

.hero-copy h2,
.page-hero h2 {
    margin: 0;
    color: var(--text);
    font-family: var(--title-font);
    font-size: var(--hero-size);
    line-height: 1.15;
    font-weight: var(--title-weight);
}

.hero-summary {
    margin: 20px 0 0;
    max-width: 720px;
    color: var(--muted);
    font-size: clamp(1rem, 1.3vw, 1.2rem);
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 24px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 42px;
    padding: 0 22px;
    border-radius: var(--button-radius);
    background: var(--accent);
    color: #fff;
    font-size: 0.95rem;
    font-weight: 500;
}

.btn:hover {
    background: var(--accent-hover);
}

.section-title {
    margin-bottom: 22px;
    text-align: left;
}

.section-title h2,
.narrative-panel h3 {
    margin: 0;
    color: var(--text);
    font-family: var(--title-font);
    font-size: clamp(1.5rem, 3vw, 2.2rem);
    line-height: 1.25;
}

.narrative-panel h3 {
    font-size: clamp(1.35rem, 2.6vw, 1.9rem);
    padding-bottom: 14px;
    border-bottom: 2px solid var(--accent);
}

.underline {
    display: none;
}

.about-content {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(260px, 0.9fr);
    gap: clamp(20px, 3vw, 32px);
    padding: 0;
    overflow: hidden;
}

.about-text {
    padding: var(--card-padding);
}

.about-text p,
.company-narrative p,
.about-full p {
    margin: 0 0 16px;
    color: var(--text);
}

.about-text p:last-child,
.company-narrative p:last-child,
.about-full p:last-child {
    margin-bottom: 0;
}

.about-image,
.visual-frame {
    min-height: 100%;
    background: #eef0f3;
}

.about-image img,
.visual-frame img {
    width: 100%;
    height: 100%;
    min-height: 260px;
    object-fit: cover;
}

.company-narrative {
    max-width: 100%;
    margin: 0;
}

.company-narrative strong {
    font-weight: 700;
}

.about-narrative {
    max-width: 100%;
    margin: 0;
}

.about-full {
    margin-top: 16px;
}

footer {
    background: var(--footer-bg);
    color: var(--footer-text);
    padding: 40px 0 24px;
    border-top: 3px solid var(--accent);
}

.footer-content {
    display: grid;
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 40px);
    padding: 0;
    border: none;
    border-radius: 0;
    background: transparent;
}

.footer-content h2,
.footer-content h3 {
    margin-top: 0;
    margin-bottom: 14px;
    color: var(--footer-text);
    font-family: var(--title-font);
    font-size: 1.15rem;
}

.footer-logo p,
.footer-bottom {
    color: var(--footer-muted);
}

.footer-social {
    text-align: right;
}

.social-links {
    display: flex;
    gap: 10px;
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border-radius: var(--button-radius);
    border: 1px solid var(--footer-border);
    color: var(--footer-muted);
    background: transparent;
}

.social-links a:hover {
    color: var(--footer-text);
    background: var(--footer-border);
}

.footer-bottom {
    padding: 20px 0 0;
    margin-top: 32px;
    text-align: left;
    border-top: 1px solid var(--footer-border);
}

.footer-bottom a {
    color: var(--footer-muted);
}

@media (max-width: 960px) {
    .about-content,
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 720px) {
    nav {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        width: 100%;
        padding: 12px 16px 16px;
        background: var(--header-bg);
        border-bottom: 1px solid var(--footer-border);
    }

    nav.active {
        display: block;
    }

    nav ul {
        flex-direction: column;
        align-items: stretch;
    }

    .mobile-menu-btn {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        width: 38px;
        height: 38px;
        border: 1px solid var(--footer-border);
        border-radius: var(--button-radius);
        cursor: pointer;
    }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .btn {
        width: 100%;
    }

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

    .social-links {
        justify-content: center;
    }
}