/* ========== Font Face ========== */
@font-face {
    font-family: 'ChillJinshuSong';
    src: url('../fonts/ChillJinshuSongHeavy.otf') format('opentype'),
         url('https://raw.githubusercontent.com/Warren2060/ChillJinshuSong/main/寒蝉锦书宋Pro_v1.7/ChillJinshuSongHeavy.otf') format('opentype');
    font-weight: 900;
    font-style: normal;
    font-display: swap;
}

/* ========== CSS Variables ========== */
:root {
    --bg: #fafaf9;
    --bg-alt: #f2f1ef;
    --bg-dark: #1a1a1a;
    --text: #1a1a1a;
    --text-secondary: #6b6b6b;
    --text-muted: #999;
    --accent: #e0552c;
    --accent-light: #f0805a;
    --accent-cyan: #0ea5b9;
    --accent-blue: #6366f1;
    --border: rgba(0, 0, 0, 0.08);
    --border-light: rgba(0, 0, 0, 0.05);
    --glass-bg: rgba(255, 255, 255, 0.6);
    --glass-border: rgba(255, 255, 255, 0.3);
    --glass-shadow: 0 8px 40px rgba(0, 0, 0, 0.06);
    --radius: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;
    --transition: 0.35s cubic-bezier(0.25, 0.1, 0.25, 1);
    --header-height: 72px;
}

/* ========== Reset & Base ========== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.75;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-weight: 400;
    font-size: 16px;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }
input, textarea { font-family: inherit; border: none; outline: none; color: inherit; }

img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* ========== Page System ========== */
.page-section {
    min-height: 100vh;
}

.page-section:not(.active) {
    display: none !important;
}

/* ========== Utility ========== */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 clamp(20px, 5vw, 60px);
}

.section { padding: clamp(80px, 12vw, 140px) 0; }

.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
}

/* ========== Section Headers ========== */
.section__label {
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 3px;
    color: var(--accent);
    margin-bottom: 16px;
    text-transform: uppercase;
}

.section__title {
    font-size: clamp(28px, 5vw, 48px);
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 16px;
    line-height: 1.2;
}

.section__sub {
    color: var(--text-secondary);
    font-size: 17px;
    max-width: 500px;
    line-height: 1.6;
}

/* ========== Buttons ========== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 15px 36px;
    border-radius: 60px;
    font-size: 15px;
    font-weight: 600;
    letter-spacing: 0.3px;
    transition: var(--transition);
}

.btn--primary {
    background: var(--accent);
    color: #fff;
}

.btn--primary:hover {
    background: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(224, 85, 44, 0.35);
}

.btn--block { width: 100%; justify-content: center; }

.link-arrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
    transition: var(--transition);
    padding-top: 24px;
}

.link-arrow:hover { gap: 14px; }

/* ========== Header ========== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    height: var(--header-height);
    background: rgba(250, 250, 249, 0.88);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border-bottom: 1px solid var(--border);
}

.nav {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: 100%;
    width: 100%;
    padding: 0 24px;
}

.nav__logo {
    justify-self: start;
}

.nav__menu {
    display: flex;
    gap: 4px;
    justify-self: center;
}

.nav__right {
    display: flex;
    align-items: center;
    gap: 12px;
    justify-self: end;
}

.nav__logo {
    display: flex;
    align-items: baseline;
    gap: 10px;
    font-weight: 700;
    z-index: 1001;
}

.nav__logo-mark {
    font-size: 20px;
    letter-spacing: 2px;
    font-weight: 800;
    color: var(--accent);
}

.nav__logo-text {
    font-size: 13px;
    letter-spacing: 3px;
    color: var(--text-secondary);
    font-weight: 500;
}

.nav__link {
    padding: 8px 18px;
    border-radius: 60px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
    letter-spacing: 0.3px;
}

.nav__link:hover, .nav__link.active {
    color: var(--text);
    background: rgba(0, 0, 0, 0.04);
}

/* ===== Language Switcher ===== */
.lang-switch {
    position: relative;
    z-index: 1001;
}

.lang-switch__btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    border-radius: 60px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    background: rgba(0, 0, 0, 0.03);
    transition: var(--transition);
    cursor: pointer;
}

.lang-switch__btn:hover {
    color: var(--text);
    background: rgba(0, 0, 0, 0.06);
}

.lang-switch__btn svg {
    width: 14px;
    height: 14px;
    transition: transform 0.25s ease;
}

.lang-switch__dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    width: 220px;
    max-height: 420px;
    overflow-y: auto;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: 0 16px 48px rgba(0, 0, 0, 0.1);
    padding: 8px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
}

.lang-switch.active .lang-switch__dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-switch.active .lang-switch__btn svg {
    transform: rotate(180deg);
}

.lang-switch__option {
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    padding: 10px 12px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
    cursor: pointer;
    text-align: left;
}

.lang-switch__option:hover {
    background: rgba(0, 0, 0, 0.04);
    color: var(--text);
}

.lang-switch__option.active {
    background: rgba(224, 85, 44, 0.08);
    color: var(--accent);
    font-weight: 600;
}

.lang-switch__option .lang-code {
    font-size: 11px;
    font-weight: 700;
    color: var(--text-muted);
    width: 24px;
    text-transform: uppercase;
}

.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 4px;
    z-index: 1001;
}

.nav__toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    transition: var(--transition);
}

.nav__toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav__toggle.active span:nth-child(2) {
    opacity: 0;
    transform: scale(0);
}

/* ========== Hero ========== */
.hero {
    position: relative;
    height: 100vh;
    min-height: 650px;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero__media {
    position: absolute;
    inset: 0;
}

.hero__image {
    position: absolute;
    inset: 0;
}

.hero__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center 30%;
}

.hero__overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(
        to right,
        rgba(26, 26, 26, 0.55) 0%,
        rgba(26, 26, 26, 0.2) 50%,
        rgba(26, 26, 26, 0.1) 100%
    );
}

.hero__body {
    position: relative;
    z-index: 1;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 clamp(20px, 5vw, 60px);
    width: 100%;
}

.hero__tagline {
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 3px;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 24px;
    text-transform: uppercase;
}

.hero__title {
    font-size: clamp(48px, 9vw, 96px);
    font-weight: 800;
    letter-spacing: -2px;
    color: #fff;
    line-height: 1.05;
    margin-bottom: 28px;
}

.hero__title-accent {
    display: block;
    font-weight: 300;
    letter-spacing: -1px;
}

.hero__desc {
    font-size: clamp(15px, 2vw, 18px);
    color: rgba(255, 255, 255, 0.75);
    max-width: 500px;
    line-height: 1.8;
    margin-bottom: 40px;
}

.hero__actions .btn--primary {
    background: #fff;
    color: var(--text);
}

.hero__actions .btn--primary:hover {
    background: #fff;
    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.2);
}

.hero__scroll {
    display: none;
}

/* ========== Brand Story ========== */
.story__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(40px, 8vw, 100px);
    align-items: center;
    margin-top: 40px;
}

.story__title {
    font-size: clamp(32px, 5vw, 52px);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.5px;
    margin-bottom: 32px;
}

.story__text p {
    color: var(--text-secondary);
    font-size: 16px;
    line-height: 1.9;
    margin-bottom: 16px;
}

.story__text strong {
    color: var(--text);
    font-weight: 600;
}

.story__image {
    position: relative;
}

.story__img-wrap {
    border-radius: var(--radius-lg);
    overflow: hidden;
    aspect-ratio: 3/4;
}

.story__accent {
    position: absolute;
    bottom: -24px;
    left: -24px;
    width: 180px;
    height: 180px;
    border-radius: 50%;
    z-index: -1;
    background: rgba(255, 255, 255, 0.5);
}

/* ========== Quote Strip ========== */
.quote-strip {
    padding: 100px 0;
    text-align: center;
}

.quote-strip__text {
    font-size: clamp(22px, 4vw, 36px);
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: -0.3px;
    color: var(--text);
}

.text-strike {
    text-decoration: line-through;
    color: var(--text-muted);
}

/* ========== Product Feature ========== */
.product-feature {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(40px, 8vw, 100px);
    align-items: center;
    padding: 80px 0;
    border-top: 1px solid var(--border-light);
}

.product-feature:first-of-type { border-top: none; padding-top: 40px; }

.product-feature--reverse .product-feature__media {
    order: 1;
}

.product-feature__media {
    position: relative;
}

.product-feature__img {
    border-radius: var(--radius-lg);
    overflow: hidden;
    aspect-ratio: 3/4;
}

.product-feature__img img {
    transition: transform 0.6s ease;
}

.product-feature__img:hover img {
    transform: scale(1.03);
}

.product-feature__img--stack {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    width: 100%;
    aspect-ratio: 3/4;
}

.product-feature__img--stack .product-feature__img {
    aspect-ratio: auto;
    height: 100%;
}

.product-feature__img--stack .product-feature__img:first-child {
    grid-row: span 2;
}

.product-feature__badge {
    position: absolute;
    top: 16px;
    left: 16px;
    padding: 6px 16px;
    border-radius: 60px;
    font-size: 12px;
    font-weight: 600;
    color: var(--text);
    z-index: 1;
}

.product-feature__tag {
    display: inline-block;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 3px;
    color: var(--accent);
    margin-bottom: 12px;
    text-transform: uppercase;
}

.product-feature__info h3 {
    font-size: clamp(28px, 4vw, 42px);
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 8px;
    line-height: 1.2;
}

.product-feature__subtitle {
    font-size: 15px;
    color: var(--text-muted);
    margin-bottom: 20px;
    letter-spacing: 0.5px;
}

.product-feature__info p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.8;
    margin-bottom: 24px;
}

.product-feature__specs {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.product-feature__specs li {
    font-size: 14px;
    color: var(--text-muted);
    padding-left: 16px;
    position: relative;
}

.product-feature__specs li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 4px;
    height: 4px;
    border-radius: 50%;
    background: var(--accent);
}

.product-feature__specs strong {
    color: var(--text-secondary);
    font-weight: 500;
}

/* ========== Values ========== */
.values__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-top: 40px;
}

.value-card {
    padding: 48px 36px;
    border-radius: var(--radius-lg);
    transition: var(--transition);
}

.value-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 16px 48px rgba(0, 0, 0, 0.08);
}


.value-card h3 {
    font-family: 'ChillJinshuSong', 'Noto Serif SC', 'STSong', 'SimSun', serif;
    font-size: 20px;
    font-weight: 900;
    margin-bottom: 12px;
    letter-spacing: 0.5px;
}

.value-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ========== Contact ========== */
.contact__wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(40px, 8vw, 100px);
    align-items: start;
}

.contact__title {
    font-size: clamp(28px, 5vw, 48px);
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: -0.5px;
}

.contact__desc {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 32px;
}

.contact__details {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 24px;
    border-radius: var(--radius-md);
    width: fit-content;
}

.contact__item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 14px;
    color: var(--text-secondary);
}

.contact__icon { font-size: 18px; }

.contact__form {
    padding: 48px 40px;
    border-radius: var(--radius-lg);
}

.form__row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 16px;
}

.form__input {
    width: 100%;
    padding: 14px 0;
    background: transparent;
    border: none;
    border-bottom: 1px solid var(--border);
    color: var(--text);
    font-size: 15px;
    transition: var(--transition);
    border-radius: 0;
}

.form__input::placeholder { color: var(--text-muted); }

.form__input:focus {
    border-bottom-color: var(--accent);
}

.form__textarea { resize: vertical; min-height: 100px; margin-bottom: 24px; }

/* ========== Footer ========== */
.footer {
    background: var(--bg-dark);
    color: #fff;
    padding: 80px 0 32px;
}

.footer__grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 64px;
}

.footer__logo {
    display: flex;
    align-items: baseline;
    gap: 10px;
    margin-bottom: 16px;
    font-weight: 800;
    font-size: 20px;
    letter-spacing: 2px;
    color: #fff;
}

.footer__logo span {
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 3px;
    color: rgba(255, 255, 255, 0.5);
}

.footer__brand p {
    color: rgba(255, 255, 255, 0.45);
    font-size: 14px;
    line-height: 1.6;
}

.footer__col h4 {
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 2px;
    margin-bottom: 20px;
    color: rgba(255, 255, 255, 0.6);
    text-transform: uppercase;
}

.footer__col a {
    display: block;
    font-size: 14px;
    color: rgba(255, 255, 255, 0.45);
    margin-bottom: 10px;
    transition: var(--transition);
}

.footer__col a:hover { color: #fff; }

.footer__bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 24px;
    text-align: center;
}

.footer__bottom p {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.3);
}

/* ========== Scroll Reveal ========== */
.reveal {
    opacity: 0;
    transform: translateY(32px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========== Responsive - Tablet ========== */
@media (max-width: 992px) {
    .hero__title { font-size: clamp(40px, 8vw, 64px); }

    .story__grid { grid-template-columns: 1fr; gap: 48px; }
    .story__image { order: -1; }
    .story__img-wrap { aspect-ratio: 4/3; }
    .story__accent { display: none; }

    .product-feature { grid-template-columns: 1fr; gap: 36px; padding: 48px 0; }
    .product-feature--reverse .product-feature__media { order: 0; }
    .product-feature__img { aspect-ratio: 4/3; }
    .product-feature__img--stack { aspect-ratio: 4/3; }

    .values__grid { grid-template-columns: 1fr; }

    .contact__wrapper { grid-template-columns: 1fr; }

    .footer__grid { grid-template-columns: 1fr 1fr; }
}

/* ========== Responsive - Mobile ========== */
@media (max-width: 768px) {
    :root { --header-height: 60px; }

    .nav {
        display: flex;
        justify-content: space-between;
    }

    .nav__menu {
        justify-self: auto;
    }

    .nav__toggle { display: flex; }

    .nav__menu {
        position: fixed;
        top: 0;
        right: -100%;
        left: auto;
        transform: none;
        width: min(300px, 80vw);
        height: 100vh;
        background: rgba(250, 250, 249, 0.97);
        backdrop-filter: blur(30px);
        -webkit-backdrop-filter: blur(30px);
        flex-direction: column;
        justify-content: center;
        gap: 4px;
        padding: 80px 40px;
        border-left: 1px solid var(--border);
        transition: right 0.4s cubic-bezier(0.25, 0.1, 0.25, 1);
        z-index: 1000;
    }

    .nav__menu.active { right: 0; }

    .nav__link { font-size: 18px; padding: 14px 20px; width: 100%; text-align: center; }

    .hero__scroll { display: none; }

    .hero { min-height: 100svh; }
    .hero__overlay {
        background: linear-gradient(
            to bottom,
            rgba(26, 26, 26, 0.2) 0%,
            rgba(26, 26, 26, 0.55) 100%
        );
    }
    .hero__title { font-size: clamp(36px, 10vw, 56px); }
    .hero__desc { font-size: 15px; }

    .story__title { font-size: clamp(24px, 6vw, 36px); }

    .values__grid { grid-template-columns: 1fr; }

    .form__row { grid-template-columns: 1fr; }

    .contact__form { padding: 32px 24px; }

    .footer__grid { grid-template-columns: 1fr; gap: 32px; }

    .section { padding: 64px 0; }
}

/* ========== Responsive - Small ========== */
@media (max-width: 480px) {
    .hero__title { font-size: 36px; }
    .product-feature__img { aspect-ratio: 1/1; }
    .product-feature__img--stack { aspect-ratio: 1/1; }
    .product-feature__img { aspect-ratio: 1/1; }
    .value-card { padding: 32px 24px; }
}

/* ========== RTL Support ========== */
html[dir="rtl"] .hero__overlay {
    background: linear-gradient(
        to left,
        rgba(26, 26, 26, 0.55) 0%,
        rgba(26, 26, 26, 0.2) 50%,
        rgba(26, 26, 26, 0.1) 100%
    );
}

html[dir="rtl"] .hero__body { direction: rtl; }
html[dir="rtl"] .hero__desc { direction: rtl; }
html[dir="rtl"] .story__text { direction: rtl; }
html[dir="rtl"] .product-feature__info { direction: rtl; }

html[dir="rtl"] .product-feature__specs li {
    padding-left: 0;
    padding-right: 16px;
}

html[dir="rtl"] .product-feature__specs li::before {
    left: auto;
    right: 0;
}

html[dir="rtl"] .lang-switch__dropdown {
    right: auto;
    left: 0;
}

html[dir="rtl"] .lang-switch__option { text-align: right; }

html[dir="rtl"] .footer { direction: rtl; }