/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #1a1a1a;
    --secondary-color: #4a4a4a;
    --accent-color: #8b7355;
    --text-primary: #1a1a1a;
    --text-secondary: #4a4a4a;
    --text-light: #6a6a6a;
    --bg-primary: #fafafa;
    --bg-secondary: #f5f5f5;
    --bg-alt: #e8e8e8;
    --border-color: #d0d0d0;
    --khaki: #8b7355;
    --khaki-light: #c9b89a;
}

body {
    font-family: 'Georgia', 'Times New Roman', serif;
    line-height: 1.8;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    font-size: 19px;
    /* 从 18px 继续增加到 19px */
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 通用链接样式 */
a {
    color: var(--text-secondary);
    text-decoration: underline;
    text-decoration-color: var(--border-color);
    text-underline-offset: 2px;
    transition: color 0.3s ease, text-decoration-color 0.3s ease;
}

a:hover {
    color: var(--khaki);
    text-decoration-color: var(--khaki);
}

a:visited {
    color: var(--text-light);
}

/* 内容区域中的链接（如描述文字中的链接） */
.timeline-description a,
.experience-description a,
.project-description a,
.talk-description a,
p a {
    color: var(--khaki);
    font-weight: 500;
    text-decoration-color: var(--khaki-light);
}

.timeline-description a:hover,
.experience-description a:hover,
.project-description a:hover,
.talk-description a:hover,
p a:hover {
    color: var(--text-primary);
    text-decoration-color: var(--text-primary);
}

/* 列表样式 */
ul,
ol {
    margin: 0.75rem 0;
    padding-left: 1.8rem;
}

ul {
    list-style-type: disc;
}

ol {
    list-style-type: decimal;
}

li {
    margin: 0.5rem 0;
    line-height: 1.75;
    color: var(--text-primary);
}

li::marker {
    color: var(--khaki);
    font-weight: 600;
}

/* 嵌套列表 */
ul ul,
ol ul {
    margin: 0.3rem 0;
    padding-left: 1.5rem;
}

ul ul li,
ol ul li {
    margin: 0.3rem 0;
}

ul ul li::marker {
    color: var(--text-secondary);
    font-weight: normal;
}

/* 描述区域内的列表特殊样式 */
.timeline-description ul,
.timeline-description ol,
.experience-description ul,
.experience-description ol,
.project-description ul,
.project-description ol,
.talk-description ul,
.talk-description ol {
    margin: 1rem 0;
    padding-left: 2rem;
}

.timeline-description li,
.experience-description li,
.project-description li,
.talk-description li {
    margin: 0.75rem 0;
    line-height: 1.8;
    font-size: 1.02rem;
}

/* 列表内的链接 */
li a {
    color: var(--khaki);
    font-weight: 500;
    text-decoration-color: var(--khaki-light);
}

li a:hover {
    color: var(--text-primary);
    text-decoration-color: var(--text-primary);
}

/* Navigation */
.navbar {
    background-color: var(--bg-primary);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 2px solid var(--text-primary);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 0;
}

.nav-brand {
    font-size: 1.1rem;
    font-weight: normal;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: 0.05em;
}

.nav-brand:hover {
    color: var(--accent-color);
}

.nav-links {
    display: flex;
    gap: 2.5rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: normal;
    font-size: 0.95rem;
    letter-spacing: 0.03em;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-color);
}

.nav-link.active {
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-underline-offset: 4px;
}

/* Section Styles */
.section {
    padding: 2.5rem 0;
    /* 从 4rem 减少到 2.5rem */
    max-width: 850px;
    /* 从 800px 增加到 850px 以容纳更大文字 */
    margin: 0 auto;
}

.section-alt {
    background-color: var(--bg-primary);
}

.section-title {
    font-size: 2.2rem;
    /* 从 2rem 增加到 2.2rem */
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
    border-bottom: 2px solid var(--text-primary);
    padding-bottom: 0.5rem;
    letter-spacing: 0.05em;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0;
    background-color: transparent;
    color: var(--text-secondary);
    text-decoration: underline;
    text-decoration-color: var(--border-color);
    text-underline-offset: 2px;
    border-radius: 0;
    font-weight: normal;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    transition: color 0.3s ease, text-decoration-color 0.3s ease;
}

.btn:hover {
    background-color: transparent;
    color: var(--khaki);
    text-decoration-color: var(--khaki);
    transform: none;
    box-shadow: none;
}

.btn:visited {
    color: var(--text-light);
}

.btn-small {
    padding: 0;
    font-size: 0.98rem;
}

.btn i {
    font-size: 0.92rem;
    color: var(--text-light);
    transition: color 0.3s ease;
}

.btn:hover i {
    color: var(--khaki);
}

/* Search Box (shared by writings & papers) */
.search-container {
    max-width: 700px;
    margin: 0 auto 2rem auto;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
    width: 100%;
    margin-bottom: 0.75rem;
}

.search-icon {
    position: absolute;
    left: 1rem;
    color: var(--text-light);
    font-size: 1rem;
    pointer-events: none;
}

.search-input {
    width: 100%;
    padding: 0.85rem 3rem 0.85rem 3rem;
    font-family: 'Georgia', serif;
    font-size: 1rem;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0;
    outline: none;
    transition: border-color 0.3s ease, background-color 0.3s ease;
}

.search-input::placeholder {
    color: var(--text-light);
    font-style: italic;
}

.search-input:focus {
    border-color: var(--khaki);
    background-color: var(--bg-primary);
}

.clear-search {
    position: absolute;
    right: 1rem;
    background: none;
    border: none;
    color: var(--text-light);
    font-size: 1rem;
    cursor: pointer;
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.3s ease;
}

.clear-search:hover {
    color: var(--text-primary);
}

.search-results-info {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-style: italic;
    min-height: 1.5rem;
}

.search-results-info.highlight {
    color: var(--khaki);
    font-weight: 500;
}

/* Filter Buttons (shared) */
.filter-buttons {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.filter-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0;
    background-color: transparent;
    color: var(--text-secondary);
    border: none;
    border-radius: 0;
    font-weight: normal;
    cursor: pointer;
    font-family: 'Georgia', serif;
    font-size: 1rem;
}

.filter-btn:hover,
.filter-btn.active {
    background-color: transparent;
    color: var(--accent-color);
    border: none;
    transform: none;
}

.filter-btn.active {
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-underline-offset: 4px;
}

.filter-btn i {
    display: none;
}

/* Pagination (shared) */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.pagination-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background-color: transparent;
    color: var(--text-primary);
    border: 1px solid var(--text-primary);
    cursor: pointer;
    font-family: 'Georgia', serif;
    font-size: 1rem;
    transition: all 0.3s;
}

.pagination-btn:hover:not(:disabled) {
    background-color: var(--text-primary);
    color: var(--bg-primary);
}

.pagination-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    border-color: var(--text-light);
    color: var(--text-light);
}

.pagination-info {
    color: var(--text-secondary);
    font-size: 1rem;
}

#current-page {
    font-weight: 600;
    color: var(--text-primary);
}

/* Footer */
.footer {
    background-color: var(--bg-primary);
    color: var(--text-light);
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
    /* 从 4rem 减少到 3rem */
    border-top: 2px solid var(--text-primary);
}

.footer p {
    margin: 0.25rem 0;
    font-size: 0.95rem;
    /* 从 0.9rem 增加到 0.95rem */
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        font-size: 15px;
    }

    .container {
        padding: 0 15px;
    }

    .nav-links {
        gap: 1.5rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .section {
        padding: 3rem 0;
    }

    .filter-buttons {
        gap: 1.5rem;
    }

    .pagination {
        flex-direction: column;
        gap: 1rem;
    }

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

    .search-container {
        margin-bottom: 1.5rem;
    }

    .search-input {
        font-size: 0.95rem;
        padding: 0.75rem 2.5rem 0.75rem 2.5rem;
    }

    .search-icon {
        left: 0.75rem;
        font-size: 0.9rem;
    }

    .clear-search {
        right: 0.75rem;
        font-size: 0.9rem;
    }

    .search-results-info {
        font-size: 0.85rem;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Selection Color */
::selection {
    background-color: var(--khaki-light);
    color: var(--text-primary);
}