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

:root {
    --navy: #1a365d;
    --navy-hover: #2d4a7c;
    --gold: #c9a227;
    --ink: #2d3748;
    --muted: #718096;
    --line: #e2e8f0;
    --page: #f7f7f5;
    --soft: #f8fafc;
    --green-soft: #f0fdf4;
    --green: #15803d;
    --red: #b91c1c;
}

html {
    scroll-behavior: smooth;
}

body {
    background: var(--page);
    color: var(--ink);
    font-family: Georgia, "Times New Roman", "Songti SC", serif;
    line-height: 1.8;
    letter-spacing: 0;
    -webkit-font-smoothing: antialiased;
}

button,
input,
select {
    letter-spacing: 0;
}

.container {
    width: min(900px, 100%);
    min-height: 100vh;
    margin: 0 auto;
    background: #fff;
}

.header {
    padding: 48px 40px;
    border-bottom: 4px solid var(--gold);
    background: var(--navy);
    text-align: center;
}

.header-title {
    margin-top: 6px;
    color: #fff;
    font-size: 32px;
    font-weight: 400;
}

.header-subtitle,
.stat-label,
.section-title,
.latest-date,
.date-item,
.back-link,
.paper-meta,
.paper-number,
.abstract-label,
.link-btn,
.paper-tag,
.category-title,
.category-count,
.cart-panel,
.sidebar,
.footer,
.empty-state {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", sans-serif;
}

.header-subtitle {
    color: rgb(255 255 255 / 70%);
    font-size: 13px;
    text-transform: uppercase;
}

.header-date {
    margin-top: 14px;
    color: var(--gold);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    font-size: 15px;
}

.summary {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border-bottom: 1px solid var(--line);
}

.summary-four {
    grid-template-columns: repeat(4, minmax(0, 1fr));
}

.stat-item {
    min-width: 0;
    padding: 22px 14px;
    border-right: 1px solid var(--line);
    text-align: center;
}

.stat-item:last-child {
    border-right: 0;
}

.stat-number {
    color: var(--navy);
    font-size: 34px;
    line-height: 1.2;
}

.stat-label {
    margin-top: 5px;
    overflow-wrap: anywhere;
    color: var(--muted);
    font-size: 10px;
    text-transform: uppercase;
}

.content {
    padding: 32px 40px 40px;
}

.section-title-row {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--line);
}

.section-title {
    color: var(--navy);
    font-size: 16px;
}

.latest-date {
    color: var(--muted);
    font-size: 12px;
}

.date-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.date-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 15px 18px;
    border-radius: 6px;
    background: var(--soft);
    color: var(--navy);
    font-size: 14px;
    text-decoration: none;
    transition: background-color 0.18s ease, color 0.18s ease;
}

.date-item:hover,
.date-item:focus-visible {
    background: var(--navy);
    color: #fff;
}

.date-meta {
    color: var(--muted);
    font-size: 12px;
}

.date-item:hover .date-meta,
.date-item:focus-visible .date-meta {
    color: rgb(255 255 255 / 72%);
}

.back-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 11px 40px;
    border-bottom: 1px solid var(--line);
    background: var(--soft);
}

.back-link {
    color: var(--navy);
    font-size: 13px;
    text-decoration: none;
}

.back-link:hover {
    color: #8a6c13;
}

.category {
    border-bottom: 1px solid var(--line);
    scroll-margin-top: 16px;
}

.category-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 40px;
    border-bottom: 1px solid var(--line);
    background: var(--soft);
}

.category-title {
    color: var(--navy);
    font-size: 16px;
}

.category-count,
.cart-title-count,
.sidebar-count {
    border-radius: 999px;
    background: #edf2f7;
    color: var(--muted);
    font-size: 11px;
}

.category-count {
    padding: 3px 10px;
}

.paper {
    padding: 30px 40px;
    border-bottom: 1px solid #f0f0f0;
    scroll-margin-top: 16px;
    transition: background-color 0.18s ease;
}

.paper:last-child {
    border-bottom: 0;
}

.paper:target,
.paper:hover {
    background: #fdfdfc;
}

.paper-number {
    margin-bottom: 8px;
    color: #8b98a9;
    font-size: 11px;
}

.paper-title {
    color: #1a202c;
    font-size: 18px;
    font-weight: 400;
    line-height: 1.5;
    overflow-wrap: anywhere;
}

.paper-title-zh {
    margin: 9px 0 15px;
    padding-left: 14px;
    border-left: 2px solid var(--gold);
    color: #4a5568;
    font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
    font-size: 14px;
}

.paper-meta {
    margin-bottom: 18px;
    color: var(--muted);
    font-size: 12px;
    overflow-wrap: anywhere;
}

.paper-categories {
    margin-top: 4px;
    color: #8b98a9;
}

.abstract-label {
    margin: 14px 0 7px;
    color: #8b98a9;
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
}

.abstract-en,
.abstract-zh {
    padding: 15px 18px;
    border-radius: 4px;
    font-size: 14px;
    line-height: 1.8;
    text-align: justify;
    overflow-wrap: anywhere;
}

.abstract-en {
    background: var(--soft);
    color: #4a5568;
}

.abstract-zh {
    border-left: 3px solid #22c55e;
    background: var(--green-soft);
    color: var(--ink);
    font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
}

.paper-actions {
    margin-top: 18px;
}

.paper-links,
.paper-tags,
.cart-actions,
.cart-ids {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.paper-tags {
    margin-top: 10px;
}

.link-btn,
.paper-tag,
.cart-action-btn {
    border-radius: 4px;
    font-size: 12px;
    cursor: pointer;
    transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

.link-btn {
    display: inline-flex;
    align-items: center;
    min-height: 34px;
    padding: 6px 13px;
    border: 1px solid transparent;
    font-weight: 500;
    text-decoration: none;
}

.link-arxiv {
    background: var(--red);
    color: #fff;
}

.link-arxiv:hover {
    background: #dc2626;
}

.link-pdf,
.link-cart {
    border-color: var(--navy);
    background: #fff;
    color: var(--navy);
}

.link-pdf:hover,
.link-cart:hover,
.link-cart.in-cart {
    background: var(--navy);
    color: #fff;
}

.link-translation {
    border-color: var(--gold);
    background: #fffbeb;
    color: #7a5b0b;
}

.link-translation:hover {
    background: var(--gold);
    color: #fff;
}

.paper-tag {
    padding: 4px 9px;
    border: 1px solid #cbd5e0;
    background: var(--soft);
    color: #4a5568;
}

.paper-tag.primary {
    border-color: var(--gold);
    background: #fffbeb;
    color: #7a5b0b;
}

.paper-tag:hover,
.paper-tag:focus-visible {
    border-color: var(--navy);
    color: var(--navy);
}

.cart-panel {
    margin: 18px 40px;
    padding: 16px 18px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
}

.cart-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}

.cart-title {
    display: flex;
    align-items: center;
    gap: 7px;
    color: var(--navy);
    font-size: 14px;
    font-weight: 600;
    white-space: nowrap;
}

.cart-title-count {
    padding: 1px 8px;
}

.cart-action-btn {
    min-height: 30px;
    padding: 5px 10px;
    border: 1px solid var(--line);
    background: #fff;
    color: #4a5568;
}

.cart-copy-btn {
    border-color: var(--navy);
    background: var(--navy);
    color: #fff;
}

.cart-action-btn:hover {
    border-color: var(--navy);
    color: var(--navy);
}

.cart-copy-btn:hover {
    background: var(--navy-hover);
    color: #fff;
}

.cart-status,
.search-status {
    min-height: 18px;
    margin-top: 8px;
    color: var(--muted);
    font-size: 11px;
}

.cart-chip {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 3px 8px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: var(--soft);
}

.cart-chip code {
    color: var(--navy);
    font-size: 11px;
}

.cart-chip-remove {
    border: 0;
    background: transparent;
    color: var(--muted);
    cursor: pointer;
}

.cart-empty {
    color: var(--muted);
    font-size: 11px;
}

.search-divider {
    margin: 14px 0;
    border-top: 1px solid var(--line);
}

.search-controls label {
    display: block;
    margin: 8px 0 3px;
    color: #4a5568;
    font-size: 11px;
    font-weight: 600;
}

.search-controls input,
.search-controls select {
    width: 100%;
    min-height: 36px;
    padding: 7px 9px;
    border: 1px solid #cbd5e0;
    border-radius: 4px;
    background: #fff;
    color: var(--ink);
    font-size: 12px;
}

.search-controls input:focus,
.search-controls select:focus {
    border-color: var(--navy);
    outline: 2px solid rgb(26 54 93 / 12%);
}

.search-results {
    display: flex;
    flex-direction: column;
    gap: 7px;
    max-height: 420px;
    overflow-y: auto;
}

.search-result {
    display: block;
    padding: 8px 9px;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: var(--soft);
    color: var(--navy);
    font-size: 11px;
    line-height: 1.5;
    text-decoration: none;
}

.search-result:hover {
    border-color: var(--navy);
}

.search-result-meta {
    display: block;
    margin-top: 3px;
    color: var(--muted);
    font-size: 10px;
}

.sidebar {
    position: fixed;
    top: 120px;
    left: max(0px, calc((100vw - 900px) / 2 - 220px));
    z-index: 200;
    width: 200px;
    max-height: calc(100vh - 160px);
    overflow-y: auto;
    padding: 16px 0;
    border-radius: 8px;
    background: #fff;
    box-shadow: 0 2px 8px rgb(0 0 0 / 8%);
}

.sidebar-title {
    padding: 0 18px 10px;
    border-bottom: 1px solid var(--line);
    color: var(--muted);
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
}

.sidebar-nav {
    list-style: none;
}

.sidebar-link {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    padding: 9px 16px;
    border-left: 3px solid var(--line);
    color: #4a5568;
    font-size: 12px;
    text-decoration: none;
}

.sidebar-link:hover,
.sidebar-link.active {
    background: var(--soft);
    color: var(--navy);
}

.progress-bar {
    position: absolute;
    top: 0;
    left: -3px;
    width: 3px;
    height: 0;
    background: var(--navy);
}

.sidebar-count {
    padding: 1px 6px;
}

.sidebar-toggle,
.back-to-top {
    z-index: 210;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 46px;
    height: 46px;
    border: 0;
    border-radius: 50%;
    background: var(--navy);
    color: #fff;
    box-shadow: 0 4px 12px rgb(26 54 93 / 28%);
    cursor: pointer;
    font-size: 20px;
}

.sidebar-toggle {
    position: static;
    display: none;
    flex: 0 0 auto;
    width: 34px;
    height: 34px;
    box-shadow: none;
    font-size: 17px;
}

.back-to-top {
    position: fixed;
    right: 24px;
    bottom: 24px;
    opacity: 0;
    pointer-events: none;
    transform: translateY(8px);
    transition: opacity 0.18s ease, transform 0.18s ease, background-color 0.18s ease;
}

.back-to-top.visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

.sidebar-toggle:hover,
.back-to-top:hover {
    background: var(--navy-hover);
}

.sidebar-overlay {
    display: none;
}

.footer {
    padding: 28px 36px;
    background: var(--navy);
    text-align: center;
}

.footer-brand {
    margin-bottom: 5px;
    color: var(--gold);
    font-family: Georgia, serif;
    font-size: 14px;
}

.footer-text,
.footer a {
    color: rgb(255 255 255 / 65%);
    font-size: 11px;
}

.empty-state {
    padding: 30px;
    color: var(--muted);
    text-align: center;
}

.daily-empty {
    min-height: 180px;
}

@media (min-width: 1420px) {
    .cart-panel {
        position: fixed;
        top: 120px;
        right: max(0px, calc((100vw - 900px) / 2 - 270px));
        z-index: 120;
        width: 250px;
        max-height: calc(100vh - 150px);
        margin: 0;
        overflow-y: auto;
        box-shadow: 0 2px 8px rgb(0 0 0 / 8%);
    }

    .cart-panel-header {
        align-items: flex-start;
        flex-direction: column;
    }
}

@media (max-width: 1300px) {
    .back-nav {
        position: sticky;
        top: 0;
        z-index: 140;
    }

    .sidebar {
        top: 0;
        left: -280px;
        width: 260px;
        height: 100vh;
        max-height: 100vh;
        border-radius: 0;
        transition: left 0.22s ease;
    }

    .sidebar.open {
        left: 0;
    }

    .sidebar-toggle {
        display: flex;
    }

    .sidebar-overlay {
        position: fixed;
        inset: 0;
        z-index: 150;
        display: block;
        background: rgb(0 0 0 / 45%);
        opacity: 0;
        pointer-events: none;
        transition: opacity 0.22s ease;
    }

    .sidebar-overlay.active {
        opacity: 1;
        pointer-events: auto;
    }
}

@media (max-width: 700px) {
    .header {
        padding: 32px 20px;
    }

    .header-title {
        font-size: 25px;
    }

    .header-subtitle {
        font-size: 11px;
        overflow-wrap: anywhere;
    }

    .summary,
    .summary-four {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .summary:not(.summary-four) {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .summary:not(.summary-four) .stat-item:nth-child(2n) {
        border-right: 1px solid var(--line);
    }

    .summary:not(.summary-four) .stat-item:nth-child(-n + 2) {
        border-bottom: 0;
    }

    .summary:not(.summary-four) .stat-item:last-child {
        border-right: 0;
    }

    .stat-item:nth-child(2n) {
        border-right: 0;
    }

    .stat-item:nth-child(-n + 2) {
        border-bottom: 1px solid var(--line);
    }

    .content,
    .paper,
    .category-header {
        padding-right: 22px;
        padding-left: 22px;
    }

    .content {
        padding-top: 24px;
    }

    .paper-title {
        font-size: 16px;
    }

    .abstract-en,
    .abstract-zh {
        padding: 13px 14px;
        text-align: left;
    }

    .paper-links .link-btn {
        flex: 1 1 calc(50% - 8px);
        justify-content: center;
        text-align: center;
    }

    .cart-panel {
        margin: 14px 12px;
    }

    .cart-panel-header,
    .section-title-row,
    .date-item {
        align-items: flex-start;
        flex-direction: column;
    }

    .back-nav {
        padding-right: 22px;
        padding-left: 22px;
    }

    .back-to-top {
        right: 16px;
        width: 44px;
        height: 44px;
    }

    .back-to-top {
        bottom: 16px;
    }
}