:root { color-scheme: light; font-family: Arial, "Microsoft YaHei", sans-serif; color: #333; background: #fff; font-size: 14px; }
* { box-sizing: border-box; }
body { margin: 0; min-width: 900px; background: #fff; }
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button { cursor: pointer; }
.sr-only { position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.top-nav { width: calc(100% - 200px); max-width: 1850px; min-width: 860px; height: 41px; margin: 8px auto 0; display: flex; align-items: stretch; border-radius: 5px 5px 0 0; overflow: hidden; background: linear-gradient(#777, #3e3e3e); box-shadow: inset 0 1px rgba(255,255,255,.25); }
.brand { width: 105px; flex: none; display: grid; place-items: center; font-size: 19px; font-weight: 900; color: #40c6f5; letter-spacing: -2px; text-shadow: 2px 1px #55d35f, 4px 1px #ffe13d; }
.top-nav nav { display: flex; overflow: hidden; }
.top-nav nav a { height: 41px; padding: 0 15px; display: grid; place-items: center; color: #f2f2f2; font-weight: 600; border-left: 1px solid rgba(0,0,0,.2); border-right: 1px solid rgba(255,255,255,.08); white-space: nowrap; }
.top-nav nav a:hover { background: rgba(0,0,0,.18); }
main { width: min(1500px, calc(100% - 520px)); min-width: 820px; margin: 8px auto 0; }
.panel { border: 1px solid #ccd0d4; border-radius: 4px; overflow: hidden; background: white; }
.search-panel { min-height: 134px; }
.search-form { display: grid; grid-template-columns: 1fr 56px; padding: 22px 21px 15px; }
.search-form > input[type="search"] { height: 37px; border: 1px solid #c7cdd3; border-radius: 4px 0 0 4px; padding: 6px 12px; outline: none; }
.search-form > input[type="search"]:focus { border-color: #1685ef; }
.search-form > button[type="submit"] { height: 37px; border: 0; border-radius: 0 4px 4px 0; color: white; background: #087ff1; }
.search-options { grid-column: 1 / -1; display: flex; align-items: center; gap: 16px; padding-top: 14px; color: #555; }
.search-options label { display: flex; align-items: center; gap: 4px; }
.search-options input { accent-color: #087ff1; }
.advanced-toggle { margin-left: auto; padding: 3px 8px; border: 0; color: #087ff1; background: transparent; }
.filters { grid-column: 1 / -1; padding: 3px 21px 13px; border-top: 1px solid #eef0f2; display: grid; grid-template-columns: 1fr 1fr; column-gap: 24px; }
.filters[hidden] { display: none; }
.filter-row { min-height: 34px; display: flex; align-items: center; }
.filter-row strong { width: 52px; flex: none; font-weight: 400; color: #777; }
.filter-row div { display: flex; flex-wrap: wrap; gap: 7px; }
.filter-row button { padding: 3px 8px; border: 0; border-radius: 10px; color: #555; background: #f3f4f5; }
.filter-row button.active { color: white; background: #1687ed; }
.results-panel { margin-top: 15px; }
.results-toolbar { height: 45px; display: flex; align-items: center; justify-content: space-between; padding: 0 13px; background: linear-gradient(#f5f5f5, #dedede); border-bottom: 1px solid #d0d0d0; }
.tabs { display: flex; align-items: center; gap: 12px; }
.tabs > span:first-child { color: #087ff1; font-size: 15px; }
.result-count { color: #8a8f94; font-size: 12px; }
.sorts { display: flex; align-items: center; color: #aaa; }
.sorts button { padding: 4px 7px; border: 0; color: #777; background: transparent; }
.sorts button.active { color: #087ff1; }
.message { margin: 8px 20px; padding: 8px 10px; color: #a15a00; background: #fff8e6; border: 1px solid #ffe1a3; }
.topic-row { min-height: 57px; display: grid; grid-template-columns: minmax(0, 1fr) 45px; align-items: center; gap: 10px; padding: 7px 20px; border-bottom: 1px solid #e4e7ea; }
.topic-row:last-child { border-bottom: 0; }
.topic-main { min-width: 0; }
.topic-title-line { display: flex; align-items: center; gap: 7px; min-width: 0; white-space: nowrap; }
.subject { min-width: 0; overflow: hidden; text-overflow: ellipsis; color: #087ff1; font-size: 15px; }
.subject:hover { text-decoration: underline; }
mark { color: #f04a50; background: transparent; }
.meta-tag { flex: none; padding: 2px 7px; border-radius: 10px; color: #4f555a; background: #f3f4f5; font-size: 12px; }
.paperclip { flex: none; color: #555; transform: rotate(-28deg); }
.topic-subline { display: flex; gap: 9px; margin-top: 5px; color: #8b9095; font-size: 12px; }
.topic-stats { justify-self: end; color: #8b949b; font-size: 12px; }
.empty { padding: 55px 15px; text-align: center; color: #888; }
.pagination { min-height: 75px; display: flex; align-items: center; justify-content: center; }
.pagination button, .pagination .ellipsis { min-width: 32px; height: 33px; margin-left: -1px; display: grid; place-items: center; border: 1px solid #d4dae0; background: white; color: #087ff1; }
.pagination button.active { color: white; background: #087ff1; border-color: #087ff1; }
.back-top { position: fixed; right: 28px; bottom: 90px; width: 42px; height: 42px; border: 1px solid #e2e4e6; color: #8a9197; background: white; box-shadow: 0 2px 10px rgba(0,0,0,.05); }
footer { width: calc(100% - 380px); min-height: 72px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; color: #6f7b86; font-size: 12px; }
@media (max-width: 1500px) { .top-nav { width: calc(100% - 40px); } main { width: calc(100% - 80px); } footer { width: calc(100% - 80px); } .top-nav nav a { padding: 0 9px; } }