/* ---------- Theme tokens (dark by default, light via system preference or toggle) ---------- */
:root {
    --bg-color: #0b0f19;
    --surface-color: #131b2e;
    --hover-color: #1a253e;
    --border-color: #243049;
    --text-main: #f1f5f9;
    --text-muted: #8b9bb4;
    --primary: #38bdf8;
    --primary-hover: #0284c7;
    --abstract-bg: #070a12;
    --ok: #10b981;
    --warn: #f59e0b;
    --err: #ef4444;
}
@media (prefers-color-scheme: light) {
    :root:not([data-theme="dark"]) {
        --bg-color: #f8fafc;
        --surface-color: #ffffff;
        --hover-color: #f1f5f9;
        --border-color: #e2e8f0;
        --text-main: #0f172a;
        --text-muted: #64748b;
        --primary: #0284c7;
        --primary-hover: #0369a1;
        --abstract-bg: #f8fafc;
    }
}
:root[data-theme="light"] {
    --bg-color: #f8fafc;
    --surface-color: #ffffff;
    --hover-color: #f1f5f9;
    --border-color: #e2e8f0;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --primary: #0284c7;
    --primary-hover: #0369a1;
    --abstract-bg: #f8fafc;
}
:root[data-theme="dark"] {
    --bg-color: #0b0f19;
    --surface-color: #131b2e;
    --hover-color: #1a253e;
    --border-color: #243049;
    --text-main: #f1f5f9;
    --text-muted: #8b9bb4;
    --primary: #38bdf8;
    --primary-hover: #0284c7;
    --abstract-bg: #070a12;
}

* { box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    margin: 0;
    padding: 0 0.75rem 2rem 0.75rem;
    line-height: 1.4;
    transition: background-color 0.15s ease, color 0.15s ease;
}
.container { max-width: 1200px; margin: 0 auto; }
.muted { color: var(--text-muted); font-weight: 400; }
.spacer { flex: 1 1 auto; }

/* ---------- Header ---------- */
header {
    padding: 0.9rem 0 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 0.85rem;
}
.header-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.6rem;
}
.brand {
    font-size: 1.35rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--text-main);
    text-decoration: none;
}
.brand span { color: var(--primary); }
.meta-bar {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    font-size: 0.82rem;
    color: var(--text-muted);
}
.badge-status {
    background-color: rgba(16, 185, 129, 0.15);
    color: var(--ok);
    padding: 0.15rem 0.45rem;
    border-radius: 4px;
    font-size: 0.75rem;
    white-space: nowrap;
}
.badge-status.warning { background-color: rgba(245, 158, 11, 0.15); color: var(--warn); }
.badge-status.error { background-color: rgba(239, 68, 68, 0.15); color: var(--err); }

.btn-small, .btn-icon, .btn-primary {
    background-color: var(--surface-color);
    color: var(--primary);
    border: 1px solid var(--border-color);
    padding: 0.2rem 0.55rem;
    border-radius: 5px;
    font-size: 0.78rem;
    text-decoration: none;
    cursor: pointer;
    white-space: nowrap;
    line-height: 1.3;
    font-family: inherit;
}
.btn-small:hover, .btn-primary:hover { background-color: var(--primary); color: #fff; border-color: var(--primary); }
.btn-icon { color: var(--text-muted); background: transparent; padding: 0.2rem 0.45rem; font-size: 0.82rem; line-height: 1; }
.btn-icon:hover { color: var(--text-main); border-color: var(--primary); }
.btn-primary { background-color: var(--primary); color: #fff; border-color: var(--primary); font-weight: 600; }
.btn-primary:hover { background-color: var(--primary-hover); }

.category-nav {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.35rem;
    margin-top: 0.65rem;
}
.cat-btn {
    background-color: var(--surface-color);
    color: var(--text-muted);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.55rem;
    border-radius: 5px;
    font-size: 0.8rem;
    text-decoration: none;
    transition: all 0.15s ease;
    cursor: pointer;
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
}
.cat-btn:hover { color: var(--text-main); border-color: var(--primary); }
.cat-btn.active {
    background-color: var(--primary);
    color: #ffffff;
    font-weight: 600;
    border-color: var(--primary);
}
.cat-btn .preset-remove {
    opacity: 0.55;
    font-size: 0.85em;
    line-height: 1;
    padding: 0 0.1rem;
}
.cat-btn .preset-remove:hover { opacity: 1; color: var(--err); }
.cat-btn.active .preset-remove:hover { color: #fff; }
.custom-cat-form { display: inline-flex; gap: 0.35rem; }
.custom-cat-form input {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 0.25rem 0.5rem;
    border-radius: 5px;
    font-size: 0.8rem;
    width: 150px;
    font-family: inherit;
}
.custom-cat-form input:focus { outline: none; border-color: var(--primary); }
.custom-cat-form button {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    color: var(--primary);
    padding: 0.25rem 0.5rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.8rem;
    font-family: inherit;
}
.custom-cat-form button:hover { background: var(--primary); color: #fff; }

/* ---------- Notices ---------- */
.alert {
    background: rgba(245, 158, 11, 0.12);
    border: 1px solid var(--warn);
    color: var(--text-main);
    padding: 0.6rem 0.8rem;
    border-radius: 6px;
    margin-bottom: 0.8rem;
    font-size: 0.85rem;
}
.alert.error { background: rgba(239, 68, 68, 0.12); border-color: var(--err); }
.alert a { color: var(--primary); }
.alert ul { margin: 0.3rem 0 0 1.1rem; padding: 0; }

/* ---------- Toolbar ---------- */
.toolbar {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.5rem 0.75rem;
    margin-bottom: 0.8rem;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 0.6rem;
}
.search-box { flex: 1 1 240px; min-width: 0; }
.search-box input {
    width: 100%;
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 0.35rem 0.65rem;
    border-radius: 5px;
    font-size: 0.85rem;
    font-family: inherit;
}
.search-box input:focus { outline: none; border-color: var(--primary); }
.toolbar-info {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    font-size: 0.8rem;
    color: var(--text-muted);
}
.cross-toggle { display: inline-flex; align-items: center; gap: 0.3rem; cursor: pointer; white-space: nowrap; }
.cross-toggle input { accent-color: var(--primary); margin: 0; }
.view-btn {
    background: transparent;
    color: var(--primary);
    border: none;
    font-size: 0.78rem;
    cursor: pointer;
    text-decoration: underline;
    padding: 0;
    white-space: nowrap;
    font-family: inherit;
}

/* ---------- Paper rows ---------- */
.papers-list {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: var(--surface-color);
    overflow: hidden;
}
.paper-item {
    padding: 0.38rem 0.65rem;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.1s ease;
}
.paper-item:last-child { border-bottom: none; }
.paper-item:hover { background-color: var(--hover-color); }
.paper-item.selected {
    background-color: var(--hover-color);
    box-shadow: inset 3px 0 0 var(--primary);
}
.paper-item[hidden] { display: none; }

.line-1 {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    white-space: nowrap;
    overflow: hidden;
    font-size: 0.92rem;
    line-height: 1.35;
}
.copy-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    padding: 0.12rem 0.28rem;
    border-radius: 4px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all 0.15s ease;
}
.copy-btn:hover { color: var(--primary); border-color: var(--primary); background: var(--bg-color); }
.copy-btn.copied { color: var(--ok); border-color: var(--ok); }
.copy-btn svg {
    width: 12px;
    height: 12px;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}
.entry-links { display: inline-flex; align-items: center; gap: 0.35rem; flex-shrink: 0; }
.mobile-links { display: none; }
.paper-id {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-size: 0.8rem;
    color: var(--primary);
    text-decoration: none;
    flex-shrink: 0;
    font-weight: 600;
}
.paper-id:hover { text-decoration: underline; }
.link-pill {
    font-size: 0.68rem;
    color: var(--text-muted);
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    padding: 0 0.28rem;
    border-radius: 3px;
    text-decoration: none;
    flex-shrink: 0;
    font-weight: 500;
    line-height: 1.35;
}
.link-pill:hover { color: var(--text-main); border-color: var(--primary); }
.type-pill {
    font-size: 0.64rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--warn);
    border: 1px solid currentColor;
    border-radius: 3px;
    padding: 0 0.25rem;
    flex-shrink: 0;
    line-height: 1.35;
    opacity: 0.85;
}
.paper-title {
    font-weight: 600;
    color: var(--text-main);
    cursor: pointer;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    flex: 1 1 auto;
    min-width: 0;
}
.paper-title:hover { color: var(--primary); }

.line-2 {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    white-space: nowrap;
    overflow: hidden;
    font-size: 0.78rem;
    color: var(--text-muted);
    line-height: 1.3;
    margin-top: 0.14rem;
}
.paper-authors {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    flex: 1 1 auto;
    min-width: 0;
}
.author-link { color: var(--text-muted); text-decoration: none; }
.author-link:hover { color: var(--primary); text-decoration: underline; }
.meta-sep { color: var(--border-color); flex-shrink: 0; }
.paper-subjects {
    color: var(--text-muted);
    opacity: 0.85;
    flex: 0 1 auto;
    max-width: 30%;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.mobile-authors { display: none; }

.paper-abstract {
    display: none;
    font-size: 0.85rem;
    color: var(--text-main);
    background: var(--abstract-bg);
    padding: 0.6rem 0.8rem;
    margin: 0.35rem 0 0.15rem 0;
    border-radius: 4px;
    border-left: 3px solid var(--primary);
    line-height: 1.5;
    white-space: normal;
}
.paper-abstract.visible { display: block; }

.empty-state { text-align: center; padding: 3rem 1rem; color: var(--text-muted); }
.empty-state h3 { margin: 0 0 0.4rem 0; color: var(--text-main); }

/* ---------- Modals ---------- */
.modal-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}
.modal-backdrop.visible { display: flex; }
.modal-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    max-width: 400px;
    width: 100%;
    padding: 1rem 1.2rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.35);
    display: flex;
    flex-direction: column;
    max-height: calc(100vh - 2rem);
}
.modal-card-wide { max-width: 760px; }
.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.75rem;
    padding-bottom: 0.45rem;
    border-bottom: 1px solid var(--border-color);
}
.modal-header h3 { margin: 0; font-size: 0.98rem; color: var(--text-main); }
.modal-close {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1.1rem;
    cursor: pointer;
    padding: 0 0.25rem;
    line-height: 1;
}
.modal-close:hover { color: var(--text-main); }
#helpModal .modal-card { max-width: 480px; overflow-y: auto; }
.shortcut-table { width: 100%; border-collapse: collapse; font-size: 0.84rem; }
.shortcut-table td { padding: 0.32rem 0; color: var(--text-main); }
.shortcut-table td:first-child { width: 38%; white-space: nowrap; }
kbd {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 0.1rem 0.38rem;
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-size: 0.78rem;
    color: var(--primary);
}

/* Category picker */
.picker-tools { display: flex; gap: 0.4rem; margin-bottom: 0.6rem; }
.picker-tools input, .picker-footer input {
    flex: 1 1 auto;
    min-width: 0;
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 0.35rem 0.6rem;
    border-radius: 5px;
    font-size: 0.85rem;
    font-family: inherit;
}
.picker-tools input:focus, .picker-footer input:focus { outline: none; border-color: var(--primary); }
.picker-body {
    overflow-y: auto;
    flex: 1 1 auto;
    min-height: 120px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    padding: 0.4rem 0.6rem;
    background: var(--bg-color);
}
.picker-group { margin-bottom: 0.6rem; }
.picker-group[hidden] { display: none; }
.picker-group-title {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--text-muted);
    margin: 0.3rem 0 0.25rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.picker-group-title button {
    background: none;
    border: none;
    color: var(--primary);
    cursor: pointer;
    font-size: 0.72rem;
    text-transform: none;
    letter-spacing: 0;
    padding: 0;
    font-family: inherit;
}
.picker-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 0.1rem 0.8rem; }
.picker-item {
    display: flex;
    align-items: baseline;
    gap: 0.4rem;
    font-size: 0.82rem;
    padding: 0.12rem 0.2rem;
    border-radius: 4px;
    cursor: pointer;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.picker-item[hidden] { display: none; }
.picker-item:hover { background: var(--hover-color); }
.picker-item input { accent-color: var(--primary); margin: 0; flex-shrink: 0; position: relative; top: 1px; }
.picker-item code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-size: 0.76rem;
    color: var(--primary);
    min-width: 6.2em;
}
.picker-item .count { color: var(--text-muted); font-size: 0.72rem; margin-left: auto; padding-left: 0.4rem; }
.picker-footer { display: flex; gap: 0.4rem; align-items: center; margin-top: 0.6rem; flex-wrap: wrap; }
.picker-footer input { flex: 0 1 200px; }

/* Options */
.modal-card-options { max-width: 520px; overflow-y: auto; }
.options-body { display: flex; flex-direction: column; gap: 0.35rem; font-size: 0.85rem; color: var(--text-main); }
.opt-label { font-weight: 600; margin-top: 0.6rem; }
.opt-label:first-child { margin-top: 0; }
.opt-help { margin: 0; color: var(--text-muted); font-size: 0.78rem; }
.opt-row { display: flex; gap: 0.4rem; }
.opt-radio { display: flex; align-items: center; gap: 0.4rem; cursor: pointer; }
.options-body textarea, .options-body select {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 0.4rem 0.6rem;
    border-radius: 5px;
    font-size: 0.82rem;
    font-family: inherit;
    width: 100%;
    box-sizing: border-box;
}
.options-body textarea { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace; resize: vertical; }
.options-body textarea:focus, .options-body select:focus { outline: none; border-color: var(--primary); }
.opt-error { color: var(--err); font-size: 0.8rem; }

/* ---------- Footer ---------- */
footer {
    margin-top: 3rem;
    padding: 1.5rem 0 0.5rem 0;
    text-align: center;
    font-size: 0.76rem;
    color: var(--text-muted);
    opacity: 0.7;
    transition: opacity 0.15s ease;
}
footer:hover { opacity: 1; }
footer a { color: var(--text-muted); text-decoration: underline; text-underline-offset: 3px; }
footer a:hover { color: var(--primary); }
#footerInfo:not(:empty)::after { content: " · "; }

/* ---------- Mobile ---------- */
@media (max-width: 640px) {
    body { padding: 0 0.5rem 1.5rem 0.5rem; }
    .desktop-only-text { display: none; }
    .category-nav {
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        padding-bottom: 2px;
    }
    .category-nav::-webkit-scrollbar { display: none; }
    .cat-btn, .custom-cat-form { flex-shrink: 0; white-space: nowrap; }
    .cat-btn { padding: 0.22rem 0.48rem; font-size: 0.76rem; }
    .custom-cat-form input { width: 110px; padding: 0.22rem 0.4rem; font-size: 0.76rem; }
    .custom-cat-form button { padding: 0.22rem 0.45rem; font-size: 0.76rem; }
    .toolbar { flex-wrap: nowrap; padding: 0.4rem 0.55rem; gap: 0.5rem; }
    .search-box { flex: 1 1 auto; }
    .search-box input { padding: 0.28rem 0.5rem; font-size: 0.8rem; }
    .toolbar-info { width: auto; flex-shrink: 0; gap: 0.45rem; white-space: nowrap; font-size: 0.76rem; }
    .view-btn { font-size: 0.75rem; }
    .line-1 { align-items: flex-start; white-space: normal; }
    .copy-btn { margin-top: 0.14rem; }
    .paper-title {
        white-space: normal;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        overflow: hidden;
        line-height: 1.3;
        font-size: 0.88rem;
    }
    .desktop-links, .desktop-authors, .paper-subjects, .desktop-sep { display: none; }
    .mobile-authors { display: block; }
    .mobile-links { display: inline-flex; align-items: center; gap: 0.25rem; flex-shrink: 0; margin-left: auto; }
    .picker-grid { grid-template-columns: 1fr; }
}