:root {
    --xlt-bg: #faf6f0;
    --xlt-bg-soft: #f3ebe2;
    --xlt-surface: #fffaf3;
    --xlt-ink: #2c2420;
    --xlt-muted: #8a7a6a;
    --xlt-line: rgba(37, 33, 30, 0.12);
    --xlt-blue: #758ca2;
    --xlt-blue-dark: #3b536b;
    --xlt-jade: #7f9b8a;
    --xlt-jade-dark: #4f6f62;
    --xlt-copper: #b8956a;
    --xlt-indigo: #42556f;
    --xlt-gold: #c4a882;
    --xlt-radius: 8px;
    --xlt-shadow: 0 22px 70px rgba(29, 39, 37, 0.13);
    --xlt-serif: "Songti SC", "STSong", "Noto Serif CJK SC", "Source Han Serif SC", Georgia, serif;
    --xlt-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--xlt-bg);
    color: var(--xlt-ink);
    font-family: var(--xlt-sans);
    font-size: 16px;
    line-height: 1.75;
    letter-spacing: 0;
}

body.xlt-nav-open {
    overflow: hidden;
}

img {
    max-width: 100%;
    height: auto;
}

a {
    color: inherit;
    text-decoration-color: rgba(40, 100, 82, 0.35);
    text-underline-offset: 0.18em;
}

a:hover {
    color: var(--xlt-jade);
}

.screen-reader-text,
.xlt-skip-link {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(1px, 1px, 1px, 1px);
}

.xlt-skip-link:focus {
    z-index: 1000;
    width: auto;
    height: auto;
    top: 14px;
    left: 14px;
    padding: 10px 14px;
    clip: auto;
    background: var(--xlt-ink);
    color: #fff;
    border-radius: var(--xlt-radius);
}

.xlt-shell {
    width: min(1160px, calc(100% - 40px));
    margin: 0 auto;
}

.xlt-site-header {
    position: sticky;
    top: 0;
    z-index: 60;
    background: rgba(246, 243, 234, 0.86);
    border-bottom: 1px solid rgba(37, 33, 30, 0.08);
    backdrop-filter: blur(18px);
}

.xlt-site-header.is-scrolled {
    box-shadow: 0 10px 30px rgba(37, 33, 30, 0.07);
}

.xlt-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 76px;
    gap: 24px;
}

.xlt-brand,
.xlt-footer-brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: var(--xlt-ink);
    text-decoration: none;
}

.xlt-brand-mark {
    display: grid;
    place-items: center;
    width: 42px;
    height: 42px;
    flex: 0 0 42px;
    border-radius: 50%;
    background: var(--xlt-jade-dark);
    color: #fff;
    font-family: var(--xlt-serif);
    font-weight: 700;
}

.xlt-brand-text {
    display: grid;
    line-height: 1.2;
}

.xlt-brand-text strong {
    font-weight: 700;
}

.xlt-brand-text small {
    max-width: 240px;
    color: var(--xlt-muted);
    font-size: 12px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.xlt-primary-nav,
.xlt-menu,
.xlt-footer-menu {
    display: flex;
    align-items: center;
    gap: 20px;
}

.xlt-menu,
.xlt-footer-menu {
    margin: 0;
    padding: 0;
    list-style: none;
}

.xlt-menu a,
.xlt-footer-nav a {
    color: var(--xlt-muted);
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
}

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

.xlt-nav-cta,
.xlt-button,
.xcp-button,
.xcp-complete-form .xcp-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 11px 18px;
    border: 1px solid var(--xlt-jade-dark);
    border-radius: var(--xlt-radius);
    background: var(--xlt-jade-dark);
    color: #fff;
    font-weight: 700;
    text-decoration: none;
    cursor: pointer;
    transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.xlt-nav-cta {
    min-height: 38px;
    padding: 8px 14px;
    font-size: 14px;
}

.xlt-button:hover,
.xlt-nav-cta:hover,
.xcp-button:hover {
    color: #fff;
    background: var(--xlt-jade);
    box-shadow: 0 12px 28px rgba(23, 62, 57, 0.18);
    transform: translateY(-1px);
}

.xlt-button-ghost {
    background: transparent;
    color: var(--xlt-jade-dark);
}

.xlt-button-ghost:hover {
    color: var(--xlt-jade-dark);
    background: rgba(40, 100, 82, 0.08);
}

.xlt-nav-toggle {
    display: none;
    width: 44px;
    height: 44px;
    border: 1px solid var(--xlt-line);
    border-radius: var(--xlt-radius);
    background: var(--xlt-surface);
}

.xlt-nav-toggle span:not(.screen-reader-text) {
    display: block;
    width: 18px;
    height: 2px;
    margin: 4px auto;
    background: var(--xlt-ink);
}

.xlt-hero {
    min-height: calc(100vh - 76px);
    display: flex;
    align-items: center;
    padding: 72px 0 56px;
    background:
        linear-gradient(90deg, rgba(250, 246, 240, 0.94) 0%, rgba(250, 246, 240, 0.74) 38%, rgba(250, 246, 240, 0.06) 74%),
        url("../img/ai-wisdom-hero.png") center / cover no-repeat;
}

.xlt-hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 430px;
    align-items: center;
    gap: 56px;
}

.xlt-kicker {
    margin: 0 0 14px;
    color: var(--xlt-copper);
    font-size: 13px;
    font-weight: 800;
    letter-spacing: 0;
    text-transform: uppercase;
}

.xlt-hero h1,
.xlt-page-hero h1,
.xlt-section-heading h2,
.xlt-letter h2 {
    margin: 0;
    color: var(--xlt-ink);
    font-family: var(--xlt-serif);
    font-weight: 700;
    line-height: 1.18;
}

.xlt-hero h1 {
    max-width: 720px;
    font-size: clamp(42px, 6vw, 78px);
}

.xlt-hero-lede {
    max-width: 620px;
    margin: 24px 0 0;
    color: #464039;
    font-size: 19px;
}

.xlt-hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 32px;
}

.xlt-hero-panel {
    position: relative;
    min-height: 460px;
    padding: 24px;
    border: 1px solid rgba(255, 255, 255, 0.65);
    border-radius: 12px;
    background: rgba(255, 250, 243, 0.72);
    box-shadow: var(--xlt-shadow);
    overflow: hidden;
}

.xlt-hero-card {
    position: relative;
    max-width: 320px;
    margin-top: 248px;
    padding: 22px;
    border: 1px solid var(--xlt-line);
    border-radius: var(--xlt-radius);
    background: var(--xlt-surface);
}

.xlt-hero-card span,
.xlt-stat span {
    display: block;
    color: var(--xlt-muted);
    font-size: 13px;
}

.xlt-hero-card strong {
    display: block;
    margin-top: 8px;
    font-family: var(--xlt-serif);
    font-size: 22px;
    line-height: 1.35;
}

.xlt-stat-row {
    position: relative;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-top: 14px;
}

.xlt-stat {
    padding: 14px;
    border: 1px solid rgba(37, 33, 30, 0.09);
    border-radius: var(--xlt-radius);
    background: rgba(255, 253, 248, 0.86);
}

.xlt-stat strong {
    display: block;
    color: var(--xlt-jade-dark);
    font-size: 20px;
}

.xlt-section {
    padding: 84px 0;
}

.xlt-courses-preview {
    background: var(--xlt-surface);
}

.xlt-section-heading {
    display: grid;
    grid-template-columns: minmax(0, 560px) minmax(240px, 1fr);
    align-items: end;
    gap: 32px;
    margin-bottom: 34px;
}

.xlt-section-heading h2,
.xlt-letter h2 {
    font-size: clamp(30px, 4vw, 48px);
}

.xlt-path-section {
    background: linear-gradient(180deg, var(--xlt-bg-soft), #fffaf3);
}

.xlt-journey-image {
    min-height: 360px;
    margin-bottom: 20px;
    border: 1px solid rgba(196, 168, 130, 0.24);
    border-radius: 12px;
    background: url("../img/learning-journey.png") center / cover no-repeat;
    box-shadow: 0 22px 72px rgba(61, 44, 30, 0.08);
}

.xlt-path-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
}

.xlt-path-card,
.xlt-card,
.xcp-course-card,
.xcp-lesson-row,
.xlt-letter-inner {
    border: 1px solid var(--xlt-line);
    border-radius: var(--xlt-radius);
    background: var(--xlt-surface);
    box-shadow: 0 12px 34px rgba(37, 33, 30, 0.06);
}

.xlt-path-card {
    padding: 24px;
}

.xlt-path-card span {
    color: var(--xlt-copper);
    font-weight: 800;
}

.xlt-path-card h3 {
    margin: 16px 0 10px;
    font-family: var(--xlt-serif);
    font-size: 22px;
}

.xlt-path-card p,
.xlt-letter p,
.xlt-card p,
.xlt-page-hero p,
.xcp-course-card-body p {
    color: var(--xlt-muted);
}

.xlt-letter {
    background:
        linear-gradient(90deg, rgba(44, 36, 32, 0.8), rgba(66, 85, 111, 0.66)),
        url("../img/ai-wisdom-hero.png") center / cover no-repeat;
    color: #fff;
}

.xlt-letter-inner {
    max-width: 900px;
    padding: 44px;
    background: rgba(255, 253, 248, 0.96);
}

.xlt-page-hero {
    padding: 76px 0 42px;
    background:
        linear-gradient(90deg, rgba(246, 243, 234, 0.94), rgba(238, 243, 237, 0.88)),
        url("../img/ai-wisdom-hero.png") center / cover no-repeat;
}

.xlt-page-hero h1 {
    max-width: 920px;
    font-size: clamp(36px, 5vw, 64px);
}

.xlt-page-hero p:not(.xlt-kicker) {
    max-width: 680px;
    margin: 16px 0 0;
    font-size: 18px;
}

.xlt-content,
.xlt-course-shell,
.xlt-lesson-shell {
    padding: 46px 0 84px;
}

.xlt-content {
    max-width: 840px;
}

.xlt-content > * {
    max-width: 760px;
}

.xlt-content h2,
.xlt-content h3 {
    font-family: var(--xlt-serif);
    line-height: 1.25;
}

.xlt-featured-media {
    margin-top: 28px;
    border-radius: 12px;
    overflow: hidden;
}

.xlt-featured-media img {
    display: block;
    width: 100%;
}

.xlt-post-grid,
.xcp-course-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.xlt-card,
.xcp-course-card {
    overflow: hidden;
}

.xlt-card-media,
.xcp-course-thumb {
    display: grid;
    place-items: center;
    min-height: 210px;
    background:
        linear-gradient(135deg, rgba(66, 85, 111, 0.26), rgba(184, 149, 106, 0.12)),
        url("../img/course-lotus-cover.png") center / cover no-repeat;
    color: #fff;
    text-decoration: none;
}

.xlt-card-media img,
.xcp-course-thumb img,
.xcp-course-hero img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.xlt-card-body,
.xcp-course-card-body {
    padding: 22px;
}

.xlt-card h2,
.xcp-course-card h3 {
    margin: 0 0 10px;
    font-family: var(--xlt-serif);
    font-size: 24px;
    line-height: 1.25;
}

.xlt-card h2 a,
.xcp-course-card h3 a {
    color: var(--xlt-ink);
    text-decoration: none;
}

.xlt-card-meta,
.xcp-course-meta,
.xcp-lesson-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 0 0 12px;
}

.xcp-course-meta span,
.xcp-lesson-meta span {
    display: inline-flex;
    align-items: center;
    min-height: 26px;
    padding: 3px 9px;
    border: 1px solid rgba(40, 100, 82, 0.16);
    border-radius: 999px;
    background: rgba(40, 100, 82, 0.07);
    color: var(--xlt-jade-dark);
    font-size: 12px;
    font-weight: 700;
}

.xcp-course {
    display: grid;
    gap: 28px;
}

.xcp-course-header {
    display: grid;
    grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1fr);
    gap: 28px;
    align-items: start;
}

.xcp-course-hero {
    min-height: 360px;
    border-radius: 12px;
    overflow: hidden;
    background:
        linear-gradient(135deg, rgba(66, 85, 111, 0.2), rgba(184, 149, 106, 0.1)),
        url("../img/course-lotus-cover.png") center / cover no-repeat;
}

.xcp-course-summary,
.xcp-lessons,
.xcp-lesson {
    padding: 30px;
    border: 1px solid var(--xlt-line);
    border-radius: var(--xlt-radius);
    background: var(--xlt-surface);
}

.xcp-course-summary p:first-of-type {
    margin-top: 0;
}

.xcp-progress {
    height: 9px;
    margin-top: 18px;
    overflow: hidden;
    border-radius: 999px;
    background: rgba(37, 33, 30, 0.09);
}

.xcp-progress span {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, var(--xlt-blue), var(--xlt-copper));
}

.xcp-progress-label {
    margin: 8px 0 0;
    color: var(--xlt-muted);
    font-size: 14px;
}

.xcp-lessons h2 {
    margin: 0 0 16px;
    font-family: var(--xlt-serif);
    font-size: 30px;
}

.xcp-lesson-list {
    display: grid;
    gap: 10px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.xcp-lesson-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 18px;
    box-shadow: none;
}

.xcp-lesson-row > div {
    min-width: 0;
}

.xcp-lesson-row a {
    font-weight: 800;
    text-decoration: none;
}

.xcp-status {
    flex: 0 0 auto;
    color: var(--xlt-copper);
    font-size: 13px;
    font-weight: 800;
}

.xcp-lesson.is-complete,
.xcp-lesson-row.is-complete {
    border-color: rgba(40, 100, 82, 0.28);
}

.xcp-video {
    margin-bottom: 28px;
    overflow: hidden;
    border-radius: 12px;
    background: #111;
}

.xcp-video iframe,
.xcp-video video {
    display: block;
    width: 100%;
    aspect-ratio: 16 / 9;
}

.xcp-back-link {
    color: var(--xlt-jade);
    font-weight: 800;
    text-decoration: none;
}

.xcp-notice,
.xlt-empty,
.xcp-empty {
    padding: 18px;
    border: 1px solid rgba(184, 112, 77, 0.24);
    border-radius: var(--xlt-radius);
    background: rgba(184, 112, 77, 0.08);
    color: #6c4936;
}

.xlt-pagination {
    grid-column: 1 / -1;
}

.xlt-site-footer {
    padding: 46px 0 24px;
    background: #172321;
    color: rgba(255, 255, 255, 0.82);
}

.xlt-plans {
    background: var(--xlt-surface);
}

.xlt-plan-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
}

.xlt-plan {
    padding: 26px;
    border: 1px solid var(--xlt-line);
    border-radius: var(--xlt-radius);
    background: linear-gradient(180deg, #fffdf9, #f8efe5);
    box-shadow: 0 18px 50px rgba(61, 44, 30, 0.07);
}

.xlt-plan.is-featured {
    border-color: rgba(184, 149, 106, 0.45);
    background:
        linear-gradient(180deg, rgba(255, 250, 243, 0.94), rgba(245, 237, 228, 0.94)),
        url("../img/course-lotus-cover.png") center / cover no-repeat;
}

.xlt-plan span {
    color: var(--xlt-copper);
    font-weight: 800;
}

.xlt-plan strong {
    display: block;
    margin: 12px 0;
    color: var(--xlt-ink);
    font-family: var(--xlt-serif);
    font-size: 36px;
}

.xlt-plan p {
    margin: 0;
    color: var(--xlt-muted);
}

.xlt-footer-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 32px;
}

.xlt-footer-brand {
    color: #fff;
    font-weight: 800;
}

.xlt-footer-grid p {
    max-width: 560px;
    color: rgba(255, 255, 255, 0.62);
}

.xlt-footer-nav {
    display: flex;
    align-items: flex-start;
    gap: 16px;
}

.xlt-footer-nav a {
    color: rgba(255, 255, 255, 0.7);
}

.xlt-footer-bottom {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    margin-top: 28px;
    padding-top: 18px;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    color: rgba(255, 255, 255, 0.48);
    font-size: 13px;
}

@media (max-width: 980px) {
    .xlt-hero-grid,
    .xcp-course-header,
    .xlt-section-heading {
        grid-template-columns: 1fr;
    }

    .xlt-hero {
        align-items: flex-start;
        min-height: 0;
        background:
            linear-gradient(180deg, rgba(250, 246, 240, 0.94), rgba(250, 246, 240, 0.78)),
            url("../img/ai-wisdom-hero.png") center / cover no-repeat;
    }

    .xlt-hero-panel {
        min-height: 360px;
    }

    .xlt-hero-card {
        margin-top: 190px;
    }

    .xlt-path-grid,
    .xlt-post-grid,
    .xcp-course-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 720px) {
    .xlt-shell {
        width: min(100% - 28px, 1160px);
    }

    .xlt-header-inner {
        min-height: 68px;
    }

    .xlt-nav-toggle {
        display: block;
    }

    .xlt-primary-nav {
        position: fixed;
        inset: 68px 14px auto 14px;
        display: none;
        flex-direction: column;
        align-items: stretch;
        padding: 18px;
        border: 1px solid var(--xlt-line);
        border-radius: 12px;
        background: var(--xlt-surface);
        box-shadow: var(--xlt-shadow);
    }

    .xlt-primary-nav.is-open {
        display: flex;
    }

    .xlt-menu {
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
    }

    .xlt-menu a {
        display: block;
        padding: 10px 0;
    }

    .xlt-brand-text small {
        display: none;
    }

    .xlt-hero {
        padding: 52px 0 40px;
    }

    .xlt-hero h1 {
        font-size: 42px;
    }

    .xlt-hero-lede,
    .xlt-page-hero p:not(.xlt-kicker) {
        font-size: 17px;
    }

    .xlt-hero-panel {
        min-height: 300px;
        padding: 16px;
    }

    .xlt-hero-card {
        margin-top: 150px;
    }

    .xlt-stat-row,
    .xlt-path-grid,
    .xlt-post-grid,
    .xcp-course-grid,
    .xlt-plan-grid,
    .xlt-footer-grid {
        grid-template-columns: 1fr;
    }

    .xlt-journey-image {
        min-height: 260px;
    }

    .xlt-section {
        padding: 58px 0;
    }

    .xlt-page-hero {
        padding: 54px 0 32px;
    }

    .xcp-course-summary,
    .xcp-lessons,
    .xcp-lesson,
    .xlt-letter-inner {
        padding: 22px;
    }

    .xcp-lesson-row {
        align-items: flex-start;
        flex-direction: column;
    }

    .xlt-footer-bottom {
        flex-direction: column;
    }
}