模板:收缩大标题/styles.css

/* ============================================
   收缩大标题
   使用 <details> / <summary> 实现零 JS 折叠
   所有内部元素用 span + display 控制
   ============================================ */

.fold {
    display: block;
    position: relative;
    margin: 1em 0;
    border-radius: 6px;
    overflow: hidden;
    background: #fff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* ---- 头部 ---- */
.fold__main {
    display: block;
    position: relative;
    padding: 1.2em 3.5em 1.2em 1.5em;
    background: #57000d;
    color: #fff;
    cursor: pointer;
    list-style: none;
    transition: background 0.3s ease;
}
.fold__main::marker {
    content: "";
}
.fold__main:hover {
    background: #6b0011;
}

/* ---- 背景水印 ---- */
.fold__watermark {
    display: block;
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    font-size: 5em;
    font-weight: 900;
    line-height: 1;
    opacity: 0.15;
    pointer-events: none;
    z-index: 0;
}

/* ---- 标题组 ---- */
.fold__titles {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    line-height: 1.2;
    position: relative;
    z-index: 1;
}
.fold__title-cn {
    display: block;
    font-size: 2.5em;
    font-weight: 900;
    letter-spacing: 0.02em;
}
.fold__title-en {
    display: block;
    font-size: 1em;
    font-weight: bold;
    letter-spacing: 0.35em;
}
.fold__title-deco {
    display: block;
    font-size: 0.8em;
    font-weight: bold;
    letter-spacing: 0.25em;
}

/* ---- 折叠按钮 ---- */
.fold__button {
    display: block;
    position: absolute;
    right: 1.2em;
    top: 50%;
    transform: translateY(-50%);
    width: 1.5em;
    height: 1.5em;
    z-index: 2;
}
.fold__button::before,
.fold__button::after {
    content: "";
    position: absolute;
    left: 50%;
    top: 50%;
    background: #fff;
    transition: transform 0.3s ease, opacity 0.3s ease;
}
.fold__button::before {
    width: 1em;
    height: 2px;
    transform: translate(-50%, -50%);
}
.fold__button::after {
    width: 2px;
    height: 1em;
    transform: translate(-50%, -50%);
}
.fold[open] .fold__button::after {
    transform: translate(-50%, -50%) rotate(90deg);
    opacity: 0;
}

/* ---- 内容区 ---- */
.fold__content {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.4s ease;
}
.fold[open] .fold__content {
    grid-template-rows: 1fr;
}
.fold__content-inner {
    display: block;
    overflow: hidden;
    padding: 0 1.5em;
    color: #333;
    line-height: 1.6;
    transition: padding 0.4s ease;
}
.fold[open] .fold__content-inner {
    padding: 1em 1.5em;
}