:root {
    --primary-color: #0078d4;
    --accent-color: #004578;
    --text-color: #323130;
    --muted-color: #605e5c;
    --line-color: #e1dfdd;
    --bg-color: #f8f9fb;
    --white: #ffffff;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-color);
    background: var(--bg-color);
}

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

.help-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--white);
    border-bottom: 1px solid var(--line-color);
}

.help-header-inner {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0.9rem 1.4rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--primary-color);
    font-weight: 700;
}

.brand small {
    color: var(--muted-color);
    font-weight: 500;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.link-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid #c8c6c4;
    border-radius: 6px;
    padding: 0.42rem 0.86rem;
    background: #fff;
    color: var(--text-color);
    font-size: 0.92rem;
}

.link-button.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: #fff;
}

.help-shell {
    max-width: 1440px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 310px minmax(0, 1fr);
    gap: 1.2rem;
    padding: 1.2rem;
}

.toc-panel {
    position: sticky;
    top: 72px;
    align-self: start;
    max-height: calc(100vh - 90px);
    overflow: auto;
    background: var(--white);
    border: 1px solid var(--line-color);
    border-radius: 10px;
    padding: 1rem;
}

.toc-title {
    margin: 0 0 0.7rem;
    font-size: 1rem;
    color: var(--primary-color);
}

.toc {
    display: flex;
    flex-direction: column;
    gap: 0.28rem;
    align-items: stretch;
    text-align: left;
}

.toc a {
    display: block;
    padding: 0.36rem 0.5rem;
    border-radius: 6px;
    color: #3b3a39;
    font-size: 0.92rem;
    text-align: left;
}

.toc a:hover,
.toc a:focus {
    background: #eef6fd;
    color: var(--accent-color);
}

.toc a.active {
    background: #eef6fd;
    color: var(--accent-color);
    font-weight: 600;
}

.toc .level-2 {
    padding-left: 1.3rem;
    font-size: 0.88rem;
    color: #4c4a48;
}

.content-panel {
    background: var(--white);
    border: 1px solid var(--line-color);
    border-radius: 10px;
    padding: 1.4rem 1.6rem 2rem;
}

.page-title {
    margin: 0;
    font-size: 1.9rem;
    color: var(--primary-color);
}

.page-desc {
    margin: 0.65rem 0 1.1rem;
    color: var(--muted-color);
}

.section {
    margin-top: 1.6rem;
    padding-top: 1rem;
    border-top: 1px solid #efedec;
}

.section:first-of-type {
    border-top: 0;
    margin-top: 0.8rem;
    padding-top: 0;
}

h2 {
    margin: 0 0 0.7rem;
    color: #1f1e1d;
}

h3 {
    margin: 1rem 0 0.5rem;
    color: #2b2a29;
}

p {
    margin: 0.45rem 0;
    line-height: 1.72;
}

ul,
ol {
    margin: 0.5rem 0 0.8rem;
    padding-left: 1.35rem;
    line-height: 1.7;
}

li + li {
    margin-top: 0.33rem;
}

.shot {
    margin: 0.9rem 0 1.2rem;
    border: 1px solid #d2d0ce;
    border-radius: 8px;
    overflow: hidden;
    background: #faf9f8;
}

.shot img {
    display: block;
    width: 100%;
    height: auto;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    background: #f3f2f1;
}

.shot figcaption {
    font-size: 0.88rem;
    color: #605e5c;
    padding: 0.55rem 0.75rem 0.7rem;
    background: #fff;
    border-top: 1px dashed #e1dfdd;
}

.tip-box {
    margin-top: 0.7rem;
    border-left: 4px solid var(--primary-color);
    background: #eff6fc;
    border-radius: 6px;
    padding: 0.6rem 0.8rem;
}

.faq-item {
    margin: 0.65rem 0;
    padding: 0.65rem 0.8rem;
    border: 1px solid #e1dfdd;
    border-radius: 7px;
}

.faq-item strong {
    color: #1f1e1d;
}

@media (max-width: 1024px) {
    .help-shell {
        grid-template-columns: 1fr;
    }

    .toc-panel {
        position: static;
        max-height: none;
    }
}