/* ============================================================
   论坛模块样式（版块 / 主题 / 楼层回复）
   与 common.css 并存，只负责论坛页；不改动全站样式
   类名前缀统一 fo- ，避免和其它模块冲突
   ============================================================ */

/* ---------- 一、论坛首页 Hero ---------- */
.fo-hero {
    position: relative;
    overflow: hidden;
    background: radial-gradient(1200px 420px at 12% -10%, rgba(107, 91, 255, .55) 0%, rgba(107, 91, 255, 0) 60%),
                radial-gradient(900px 380px at 88% 0%, rgba(59, 109, 246, .5) 0%, rgba(59, 109, 246, 0) 62%),
                linear-gradient(135deg, #16204a 0%, #22307a 52%, #2b2a86 100%);
    color: #fff;
    padding: 46px 0 52px;
}

.fo-hero-inner {
    display: flex;
    align-items: center;
    gap: 30px;
}

.fo-hero-text { flex: 1; min-width: 0; }

.fo-hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 5px 13px;
    border-radius: 999px;
    background: rgba(255, 255, 255, .14);
    border: 1px solid rgba(255, 255, 255, .22);
    font-size: 12.5px;
    letter-spacing: .4px;
    backdrop-filter: blur(6px);
}

.fo-hero-title {
    margin: 14px 0 10px;
    font-size: 44px;
    line-height: 1.12;
    font-weight: 900;
    letter-spacing: 2px;
    text-shadow: 0 6px 24px rgba(0, 0, 0, .28);
}

.fo-hero-title em {
    font-style: normal;
    background: linear-gradient(120deg, #8fb4ff 0%, #c7b8ff 60%, #fff 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.fo-hero-sub {
    max-width: 640px;
    font-size: 14.5px;
    line-height: 1.75;
    color: rgba(255, 255, 255, .82);
}

.fo-hero-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 34px;
    margin-top: 24px;
}

.fo-hero-stat b {
    display: block;
    font-size: 26px;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: .5px;
}

.fo-hero-stat span {
    font-size: 12.5px;
    color: rgba(255, 255, 255, .62);
}

.fo-hero-deco {
    position: relative;
    width: 220px;
    height: 140px;
    flex: none;
}

.fo-hero-deco .fo-ring {
    position: absolute;
    border-radius: 50%;
    border: 1px solid rgba(255, 255, 255, .18);
}

.fo-ring-1 { width: 140px; height: 140px; right: 70px; top: 0; background: rgba(255, 255, 255, .06); }
.fo-ring-2 { width: 88px; height: 88px; right: 6px; top: 30px; background: rgba(255, 255, 255, .08); }
.fo-ring-3 { width: 46px; height: 46px; right: 128px; top: 92px; background: rgba(255, 255, 255, .1); }

.fo-hero-deco .fo-deco-emoji {
    position: absolute;
    right: 108px;
    top: 44px;
    font-size: 34px;
    filter: drop-shadow(0 6px 14px rgba(0, 0, 0, .25));
}

/* ---------- 二、区块标题 ---------- */
.fo-sec {
    margin: 30px 0 34px;
}

.fo-sec-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    margin-bottom: 16px;
}

.fo-sec-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 800;
    letter-spacing: .5px;
}

.fo-sec-title::before {
    content: "";
    width: 4px;
    height: 18px;
    border-radius: 3px;
    background: var(--grad, linear-gradient(135deg, #3b6df6, #6b5bff));
}

.fo-sec-tip { color: var(--text-3); font-size: 13px; }

.fo-sec-link {
    color: var(--brand, #3b6df6);
    font-size: 13.5px;
    font-weight: 600;
}

.fo-sec-link:hover { text-decoration: underline; }

/* ---------- 三、版块卡片（首页） ---------- */
.fo-boards {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
}

.fo-board {
    display: block;
    background: #fff;
    border: 1px solid var(--border, #e8ebf3);
    border-radius: 16px;
    overflow: hidden;
    transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.fo-board:hover {
    transform: translateY(-3px);
    box-shadow: 0 16px 36px rgba(22, 32, 74, .12);
    border-color: #d7dffb;
    color: var(--text, #1f2330);
}

.fo-board-top {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 18px 14px;
    color: #fff;
    position: relative;
    overflow: hidden;
}

.fo-board-top::after {
    content: "";
    position: absolute;
    right: -30px;
    top: -40px;
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: rgba(255, 255, 255, .14);
}

.fo-board-ico {
    width: 44px;
    height: 44px;
    flex: none;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    background: rgba(255, 255, 255, .22);
    border: 1px solid rgba(255, 255, 255, .3);
    font-size: 22px;
    backdrop-filter: blur(4px);
}

.fo-board-ico img {
    width: 100%;
    height: 100%;
    border-radius: 12px;
    object-fit: cover;
}

.fo-board-name {
    font-size: 17px;
    font-weight: 800;
    letter-spacing: .5px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, .18);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.fo-board-body { padding: 14px 18px 16px; }

.fo-board-intro {
    min-height: 40px;
    color: var(--text-2, #5b6472);
    font-size: 13px;
    line-height: 1.65;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.fo-board-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 14px;
    padding-top: 12px;
    border-top: 1px dashed var(--border, #e8ebf3);
    color: var(--text-3);
    font-size: 12.5px;
}

.fo-board-meta b { color: var(--text, #1f2330); font-weight: 700; }

.fo-board-go {
    display: inline-flex;
    align-items: center;
    gap: 3px;
    padding: 3px 10px;
    border-radius: 999px;
    background: var(--brand-light, #eef1ff);
    color: var(--brand, #3b6df6);
    font-weight: 700;
}

/* ---------- 四、主题列表（行式） ---------- */
.fo-list {
    background: #fff;
    border: 1px solid var(--border, #e8ebf3);
    border-radius: 16px;
    overflow: hidden;
}

.fo-list-head {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 84px 74px 140px;
    gap: 12px;
    padding: 12px 20px;
    background: #f7f9ff;
    border-bottom: 1px solid var(--border, #e8ebf3);
    color: var(--text-3);
    font-size: 12.5px;
    letter-spacing: .5px;
}

.fo-topic {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 84px 74px 140px;
    gap: 12px;
    align-items: center;
    padding: 14px 20px;
    border-bottom: 1px solid #f1f3f9;
    transition: background .15s ease;
}

.fo-topic:last-child { border-bottom: none; }
.fo-topic:hover { background: #fafbff; color: var(--text, #1f2330); }

.fo-topic-main { min-width: 0; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

.fo-tag {
    flex: none;
    padding: 1px 7px;
    border-radius: 5px;
    font-size: 11.5px;
    font-weight: 700;
    letter-spacing: .3px;
}

.fo-tag-top { background: #fff1e6; color: #d97706; }
.fo-tag-essence { background: #e7f5ff; color: #0e7490; }
.fo-tag-board { background: #eef1ff; color: #3b6df6; font-weight: 600; }

.fo-topic-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text, #1f2330);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    max-width: 100%;
}

.fo-topic:hover .fo-topic-title { color: var(--brand, #3b6df6); }

.fo-topic-sub {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-3);
    font-size: 12.5px;
}

.fo-topic-sub img,
.fo-avatar-sm {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    object-fit: cover;
    flex: none;
}

.fo-topic-num { color: var(--text-2); font-size: 13px; text-align: center; }
.fo-topic-num b { font-weight: 700; color: var(--text, #1f2330); }
.fo-topic-last { color: var(--text-3); font-size: 12.5px; text-align: right; }

.fo-has-img { color: var(--text-3); display: inline-flex; }

/* ---------- 五、版块页头部 ---------- */
.fo-boardhead {
    position: relative;
    overflow: hidden;
    color: #fff;
    padding: 30px 0 34px;
}

.fo-boardhead-inner {
    display: flex;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap;
}

.fo-boardhead-ico {
    width: 72px;
    height: 72px;
    flex: none;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 18px;
    background: rgba(255, 255, 255, .2);
    border: 1px solid rgba(255, 255, 255, .34);
    font-size: 34px;
    backdrop-filter: blur(6px);
    box-shadow: 0 10px 26px rgba(0, 0, 0, .16);
}

.fo-boardhead-ico img {
    width: 100%;
    height: 100%;
    border-radius: 18px;
    object-fit: cover;
}

.fo-boardhead-text { flex: 1; min-width: 220px; }

.fo-boardhead-name {
    font-size: 30px;
    font-weight: 900;
    letter-spacing: 1px;
    line-height: 1.25;
    text-shadow: 0 3px 14px rgba(0, 0, 0, .2);
}

.fo-boardhead-intro {
    margin-top: 6px;
    font-size: 14px;
    color: rgba(255, 255, 255, .9);
    max-width: 720px;
}

.fo-boardhead-meta {
    display: flex;
    gap: 20px;
    margin-top: 12px;
    font-size: 13px;
    color: rgba(255, 255, 255, .86);
}

.fo-boardhead-meta b { font-size: 15px; font-weight: 800; }

.fo-boardhead-actions { display: flex; gap: 12px; align-items: center; }

.fo-join-btn {
    background: rgba(255, 255, 255, .18);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, .7);
    font-weight: 700;
}

.fo-join-btn:hover { background: #fff; color: var(--brand, #3b6df6); }

.fo-join-btn.joined {
    background: #fff;
    color: var(--green, #22c55e);
    border-color: #fff;
    font-weight: 800;
}

/* ---------- 六、工具条 / 排序 ---------- */
.fo-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    flex-wrap: wrap;
    margin: 22px 0 14px;
}

.fo-tabs { display: flex; gap: 8px; }

.fo-tab {
    padding: 6px 15px;
    border-radius: 999px;
    border: 1px solid var(--border, #e8ebf3);
    background: #fff;
    color: var(--text-2, #5b6472);
    font-size: 13.5px;
    font-weight: 600;
}

.fo-tab.active {
    background: var(--grad, linear-gradient(135deg, #3b6df6, #6b5bff));
    border-color: transparent;
    color: #fff;
    box-shadow: 0 8px 18px rgba(59, 109, 246, .26);
}

.fo-toolbar-tip { color: var(--text-3); font-size: 13px; }

/* ---------- 七、帖子详情（楼层式） ---------- */
.fo-thread {
    background: #fff;
    border: 1px solid var(--border, #e8ebf3);
    border-radius: 16px;
    overflow: hidden;
    margin-top: 16px;
}

.fo-thread-head { padding: 24px 26px 20px; border-bottom: 1px solid #f1f3f9; }

.fo-thread-title {
    font-size: 25px;
    font-weight: 800;
    line-height: 1.38;
    letter-spacing: .5px;
}

.fo-thread-sub {
    display: flex;
    align-items: center;
    gap: 14px;
    flex-wrap: wrap;
    margin-top: 12px;
    color: var(--text-3);
    font-size: 13px;
}

.fo-thread-sub img {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    object-fit: cover;
}

.fo-thread-author { color: var(--text-2); font-weight: 700; display: inline-flex; align-items: center; gap: 8px; }

.fo-floor {
    display: flex;
    gap: 0;
    border-bottom: 1px solid #f1f3f9;
}

.fo-floor:last-child { border-bottom: none; }

.fo-floor-side {
    width: 132px;
    flex: none;
    padding: 20px 12px;
    background: #f9fafd;
    border-right: 1px solid #f1f3f9;
    text-align: center;
}

.fo-floor-side .fo-floor-avatar {
    width: 58px;
    height: 58px;
    margin: 0 auto;
    border-radius: 50%;
    overflow: hidden;
    background: linear-gradient(135deg, #3b6df6, #6b5bff);
    color: #fff;
    font-size: 22px;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
}

.fo-floor-side .fo-floor-avatar img { width: 100%; height: 100%; object-fit: cover; }

.fo-floor-name {
    margin-top: 9px;
    font-size: 13.5px;
    font-weight: 700;
    color: var(--text, #1f2330);
    word-break: break-all;
}

.fo-floor-badge {
    display: inline-block;
    margin-top: 6px;
    padding: 1px 8px;
    border-radius: 999px;
    font-size: 11.5px;
    background: #eef1ff;
    color: #3b6df6;
    font-weight: 700;
}

.fo-floor-body { flex: 1; min-width: 0; padding: 18px 22px 22px; }

.fo-floor-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding-bottom: 12px;
    border-bottom: 1px dashed #f0f2f8;
    color: var(--text-3);
    font-size: 12.5px;
}

.fo-floor-no {
    font-weight: 700;
    color: var(--brand, #3b6df6);
    background: var(--brand-light, #eef1ff);
    padding: 2px 10px;
    border-radius: 999px;
}

.fo-floor-content {
    padding-top: 14px;
    font-size: 15px;
    line-height: 1.85;
    color: var(--text, #1f2330);
    word-break: break-word;
}

.fo-floor-content img { max-width: 100%; border-radius: 10px; margin: 8px 0; }
.fo-floor-content p { margin: 0 0 10px; }
.fo-floor-content blockquote {
    margin: 10px 0;
    padding: 10px 14px;
    border-left: 3px solid #d7dffb;
    background: #f7f9ff;
    border-radius: 0 8px 8px 0;
    color: var(--text-2);
}

.fo-floor-imgs { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; }

.fo-floor-imgs a img {
    width: 132px;
    height: 132px;
    object-fit: cover;
    border-radius: 10px;
    border: 1px solid var(--border, #e8ebf3);
}

.fo-op-mark {
    display: inline-block;
    margin-left: 6px;
    padding: 1px 8px;
    border-radius: 999px;
    background: linear-gradient(135deg, #3b6df6, #6b5bff);
    color: #fff;
    font-size: 11.5px;
    font-weight: 700;
}

/* ---------- 八、回复框 ---------- */
.fo-replybox {
    background: #fff;
    border: 1px solid var(--border, #e8ebf3);
    border-radius: 16px;
    padding: 20px 22px 22px;
    margin: 18px 0 34px;
}

.fo-replybox-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 17px;
    font-weight: 800;
    margin-bottom: 14px;
}

/* ---------- 九、侧栏 ---------- */
.fo-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 296px;
    gap: 20px;
    align-items: start;
}

.fo-side-card {
    background: #fff;
    border: 1px solid var(--border, #e8ebf3);
    border-radius: 16px;
    padding: 16px 18px 18px;
    margin-bottom: 16px;
}

.fo-side-card h3 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 15.5px;
    font-weight: 800;
    margin-bottom: 12px;
}

.fo-hot-item {
    display: flex;
    gap: 9px;
    padding: 9px 0;
    border-bottom: 1px dashed #f0f2f8;
    font-size: 13.5px;
    color: var(--text, #1f2330);
}

.fo-hot-item:last-child { border-bottom: none; }

.fo-hot-no {
    flex: none;
    width: 18px;
    height: 18px;
    line-height: 18px;
    text-align: center;
    border-radius: 5px;
    background: #f1f4ff;
    color: #3b6df6;
    font-size: 12px;
    font-weight: 800;
}

.fo-hot-no.top { background: linear-gradient(135deg, #ff7a45, #ff4d4f); color: #fff; }

.fo-hot-title {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.fo-hot-item:hover .fo-hot-title { color: var(--brand, #3b6df6); }

.fo-quick-board {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.fo-quick-board a {
    padding: 5px 12px;
    border-radius: 999px;
    background: #f5f7ff;
    color: var(--text-2, #5b6472);
    font-size: 13px;
}

.fo-quick-board a:hover { background: var(--brand-light, #eef1ff); color: var(--brand, #3b6df6); }

/* ---------- 十、发主题 / 编辑 ---------- */
.fo-form-card {
    background: #fff;
    border: 1px solid var(--border, #e8ebf3);
    border-radius: 16px;
    padding: 24px 26px 26px;
    margin: 16px 0 34px;
}

.fo-form-head {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 18px;
    padding-bottom: 14px;
    border-bottom: 1px solid #f1f3f9;
}

.fo-form-head h2 { font-size: 19px; font-weight: 800; }
.fo-form-head small { color: var(--text-3); font-size: 13px; }

/* ---------- 十一、响应式 ---------- */
@media (max-width: 992px) {
    .fo-boards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .fo-layout { grid-template-columns: minmax(0, 1fr); }
    .fo-hero-deco { display: none; }
}

@media (max-width: 768px) {
    .fo-hero { padding: 30px 0 34px; }
    .fo-hero-title { font-size: 30px; letter-spacing: 1px; }
    .fo-hero-sub { font-size: 13px; }
    .fo-hero-stats { gap: 22px; margin-top: 18px; }
    .fo-hero-stat b { font-size: 20px; }

    .fo-boardhead { padding: 22px 0 24px; }
    .fo-boardhead-ico { width: 56px; height: 56px; font-size: 26px; border-radius: 14px; }
    .fo-boardhead-name { font-size: 22px; }
    .fo-boardhead-intro { font-size: 13px; }
    .fo-boardhead-actions { width: 100%; }

    .fo-list-head { display: none; }

    .fo-topic {
        grid-template-columns: minmax(0, 1fr);
        gap: 6px;
        padding: 13px 14px;
    }

    .fo-topic-title { font-size: 14.5px; white-space: normal; }

    .fo-topic-numbar {
        display: flex;
        gap: 14px;
        color: var(--text-3);
        font-size: 12px;
    }

    .fo-topic-last { text-align: left; font-size: 12px; }

    /* 楼层：手机端头像行上置，避免左右挤压 */
    .fo-floor { flex-direction: column; }
    .fo-floor-side {
        width: auto;
        display: flex;
        align-items: center;
        gap: 10px;
        text-align: left;
        padding: 12px 14px 0;
        background: transparent;
        border-right: none;
    }
    .fo-floor-side .fo-floor-avatar {
        width: 36px;
        height: 36px;
        margin: 0;
        font-size: 15px;
    }
    .fo-floor-name { margin-top: 0; font-size: 13px; }
    .fo-floor-badge { margin-top: 0; }
    .fo-floor-body { padding: 10px 14px 16px; }
    .fo-floor-content { font-size: 14.5px; line-height: 1.8; }
    .fo-thread-title { font-size: 19px; }
    .fo-thread-head { padding: 16px 16px 14px; }
    .fo-floor-imgs a img { width: 96px; height: 96px; }
    .fo-form-card { padding: 16px 14px 18px; }
    .fo-replybox { padding: 14px; }
}

@media (max-width: 560px) {
    .fo-boards { grid-template-columns: minmax(0, 1fr); }
    .fo-hero-stats { gap: 16px; }
}