/* ========== 全局 ========== */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Georgia', 'Noto Serif SC', 'Songti SC', serif;
    background-color: #F5F1EB;
    color: #4a3728;
    line-height: 1.6;
    overflow-x: hidden;
}

/* ========== 导航栏 ========== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: #A87868;
    z-index: 1000;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: -5px;  /* 图片和文字的间距 */
    margin-left: -160px;  /* 负值往左移，自己调数值 */
    font-size: 1.5em;
    font-weight: bold;
    color: #F5F1EB;
    text-decoration: none;
    letter-spacing: 3px;
    font-family: 'Georgia', serif;
}

.logo-img {
    height: 80px;   /* 图片高度，跟导航栏协调 */
    width: auto;
    object-fit: contain;
}
.nav-links {
    list-style: none;
    display: flex;
    gap: 8px;
}

.nav-links a {
    color: #F5F1EB;
    text-decoration: none;
    padding: 8px 18px;
    border-radius: 20px;
    font-size: 0.95em;
    transition: all 0.3s ease;
    letter-spacing: 1px;
}

.nav-links a:hover,
.nav-links a.active {
    background-color: rgba(245, 241, 235, 0.2);
    color: #fff;
}

/* ========== 主体 ========== */
.main-content {
    padding-top: 130px;
    padding-bottom: 60px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.page-title {
    font-size: 3.3em;
    color: #4a3728;
    letter-spacing: 5px;
    margin-bottom: 40px;
    text-align: center;
}

/* ========== 时间轴横幅 ========== */

.timeline-row {
    width: 100%;
    max-width: 1400px;
    margin-bottom: -20px;
}

.period-items {
    position: relative;
    width: 100%;
    height: 280px;
    display: flex;
    justify-content: space-between;
    padding: 0 12%;
    background-size: 100% auto;
    background-position: center;
    background-repeat: no-repeat;
}


.row-1 {
    margin-top: 60px;
}
.row-1 .period-items {
    background-image: url('./picture/timeline-bg1.png');
}


.row-2 .period-items {
    background-image: url('./picture/timeline-bg2.png');
}

.period-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    position: relative;
}

.period-item:hover .period-year,
.period-item:hover .period-name {
    text-shadow: 3px 3px 12px rgba(0, 0, 0, 0.8);
}

/* 文字内容 */
.period-year {
    font-size: 3.2em;
    font-weight: bold;
    color: #fff;
    letter-spacing: 2px;
    line-height: 1;
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.5);
    transition: text-shadow 0.3s ease;
}

.period-year::before {
    content: '>';
    font-size: 0.75em;
    margin-right: 4px;
    opacity: 0.8;
}

.period-name {
    font-size: 1.25em;
    color: #fff;
    letter-spacing: 2px;
    text-decoration: underline;
    text-underline-offset: 6px;
    text-shadow: 1px 1px 6px rgba(0, 0, 0, 0.5);
    margin-top: 12px;
    text-align: center;
    transition: text-shadow 0.3s ease;
}

/* 行2的"至今"小字 */
.period-suffix {
    font-size: 0.35em;
    margin-left: 8px;
    opacity: 0.9;
    vertical-align: middle;
}

/* 悬停简介 tooltip */
.period-brief {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(74, 55, 40, 0.95);
    color: #F5F1EB;
    padding: 14px 22px;
    border-radius: 8px;
    font-size: 0.9em;
    line-height: 1.7;
    width: 340px;
    text-align: left;
    letter-spacing: 1px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    z-index: 999;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
}

/* 行1的brief在上方 */
.row-1 .period-brief { bottom: calc(100% - 30px); }
.row-1 .period-brief::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 10px solid transparent;
    border-top-color: rgba(74, 55, 40, 0.95);
}

/* 行2的brief在下方 */
.row-2 .period-brief { top: calc(100% - 30px); }
.row-2 .period-brief::after {
    content: '';
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 10px solid transparent;
    border-bottom-color: rgba(74, 55, 40, 0.95);
}

.period-item:hover .period-brief {
    opacity: 1;
}

/* ========== 页脚 ========== */
.footer {
    background-color: #A87868;
    color: #F5F1EB;
    text-align: center;
    padding: 30px;
    font-size: 0.9em;
    letter-spacing: 1px;
    margin-top: 40px;
}

/* ========== 响应式 ========== */
@media (max-width: 900px) {
    .period-items {
        height: 240px;
    }
    
    .period-year {
        font-size: 2.4em;
    }
    
    .period-name {
        font-size: 1em;
    }
}

@media (max-width: 600px) {
    .page-title {
        font-size: 1.5em;
    }
    
    .period-items {
        height: 200px;
    }
    
    .period-year {
        font-size: 1.8em;
    }
    
    .period-name {
        font-size: 0.85em;
    }
    
    .nav-links a {
        padding: 6px 10px;
        font-size: 0.82em;
    }
}

/* ========== 装饰弯钩图 ========== */
.timeline-row {
    position: relative;
}

.decor-img {
    position: absolute;
    
    width: auto;
    z-index: 1;
    pointer-events: none;
    bottom: 0;
}

.row-1 .decor-right { height: 260px; bottom: 63px; margin-left: -2px; }
.row-2 .decor-left { height: 267px; bottom: -51px; margin-right: -2px;}

.decor-left { right: calc(100%); }
.decor-right { left: calc(100%); }

@media (max-width: 1600px) { .decor-img { display: none; } }