feat(ui): densify home and ranking video cards

Drop nested home panels, overlay rank and duration on covers, and keep
metrics fully visible by moving dates onto the author row.

reaction_board/web/static/style.css

@@ -297,6 +297,7 @@ h1, h2, h3, strong, b { font-weight: 600; }
   margin-bottom: 8px;
 }
 .section-head h2 { font-size: 16px; font-weight: 600; }
+.home-block { min-width: 0; }
 .section-note { color: var(--muted); font-size: 12px; margin: 0 0 12px; }
 .warning-text { color: var(--warning); }
 .danger { color: var(--danger); }
@@ -343,8 +344,7 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
 .video-card, .up-card {
   position: relative;
   display: grid;
-  grid-template-columns: 24px 96px minmax(0, 1fr);
-  align-items: start;
+  align-items: stretch;
   gap: 12px;
   padding: 10px;
   border: 1px solid var(--border);
@@ -353,50 +353,75 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   transition: border-color 0.15s cubic-bezier(0.22, 1, 0.36, 1),
     background-color 0.15s cubic-bezier(0.22, 1, 0.36, 1);
 }
+.video-card { grid-template-columns: 128px minmax(0, 1fr); }
+.up-card { grid-template-columns: 64px minmax(0, 1fr); align-items: center; }
 .video-card:hover, .up-card:hover {
   border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
   background: color-mix(in srgb, var(--accent) 5%, var(--surface));
 }
-.video-card.no-rank, .up-card.no-rank { grid-template-columns: 96px minmax(0, 1fr); }
-.video-card.no-rank .video-thumb, .up-card.no-rank .video-thumb { grid-column: 1; }
-.video-card.no-rank .video-card-body, .up-card.no-rank .up-card-body { grid-column: 2; }
+.video-cover, .media-cover, .up-cover { position: relative; overflow: hidden; }
+.video-cover, .media-cover { border-radius: 6px; }
+.up-cover { width: 64px; height: 64px; }
 .rank-badge {
-  grid-column: 1;
-  grid-row: 1;
-  align-self: start;
+  position: absolute;
+  z-index: 1;
+  top: 0;
+  left: 0;
   display: grid;
   place-items: center;
-  width: 24px;
-  height: 24px;
-  border-radius: 6px;
-  background: transparent;
-  color: var(--muted);
+  min-width: 28px;
+  height: 22px;
+  padding: 0 7px;
+  border-radius: inherit;
+  border-top-right-radius: 0;
+  border-bottom-right-radius: 0;
+  border-bottom-left-radius: 0;
+  background: rgba(0, 0, 0, 0.54);
+  color: #fff;
   font-size: 13px;
   font-weight: 600;
+  line-height: 1;
+  pointer-events: none;
+  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.55);
+}
+.rank-badge.rank-1 {
+  background: color-mix(in srgb, var(--accent) 70%, transparent);
+  color: #fff;
+}
+.cover-duration {
+  position: absolute;
+  z-index: 1;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  display: flex;
+  justify-content: flex-end;
+  align-items: center;
+  padding: 4px 6px;
+  background: rgba(0, 0, 0, 0.4);
+  color: #fff;
+  font-size: 11px;
+  font-weight: 400;
+  line-height: 1;
+  pointer-events: none;
+  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.55);
 }
-.rank-badge.rank-1 { background: var(--accent); color: var(--accent-contrast); }
-.rank-badge.rank-2, .rank-badge.rank-3 { background: var(--surface-2); color: var(--text); }
 .video-thumb, .hero-cover, .media-thumb, .candidate-thumb {
   position: relative;
   overflow: hidden;
   border-radius: 6px;
   background: var(--surface-2);
 }
-.video-thumb {
-  grid-column: 2;
-  grid-row: 1;
-  width: 96px;
-  aspect-ratio: 16 / 9;
-}
+.video-thumb { width: 100%; aspect-ratio: 16 / 9; }
 .video-thumb img, .hero-cover img, .media-thumb img, .candidate-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
 .cover-placeholder { display: grid; place-items: center; color: var(--muted); font-size: 11px; }
 .cover-placeholder img.image-error { opacity: 0; }
-.video-card-body, .up-card-body { grid-column: 3; grid-row: 1; min-width: 0; }
+.video-card-body, .up-card-body {
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+}
 .up-avatar {
-  grid-column: 2;
-  grid-row: 1;
-  justify-self: center;
-  align-self: center;
   width: 64px;
   height: 64px;
   border-radius: 50%;
@@ -409,7 +434,6 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   font-weight: 600;
 }
 .up-avatar img { width: 100%; height: 100%; object-fit: cover; display: block; }
-.up-card.no-rank > .up-avatar { grid-column: 1; }
 .avatar-placeholder { text-transform: uppercase; }
 .video-title {
   display: -webkit-box;
@@ -420,8 +444,26 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   line-height: 1.35;
   font-weight: 600;
 }
-/* 标题固定占两行高度（line-height 1.35 × 2），让单行与两行标题的行高一致。 */
-.video-card .video-title, .media-title { min-height: 2.7em; }
+/* 标题固定占两行高度，让单行与两行标题的卡片高度一致。 */
+.video-card .video-title { min-height: 2.7em; }
+.media-title { min-height: 2.8em; }
+.video-byline {
+  display: flex;
+  align-items: baseline;
+  justify-content: space-between;
+  gap: 8px;
+  margin-top: 4px;
+  min-width: 0;
+}
+.video-up {
+  min-width: 0;
+  flex: 1 1 auto;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: var(--muted);
+  font-size: 12px;
+}
 .video-meta {
   display: flex;
   flex-wrap: wrap;
@@ -434,12 +476,24 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   display: flex;
   flex-wrap: wrap;
   align-items: baseline;
-  gap: 4px 10px;
+  gap: 4px 8px;
   margin-top: 6px;
   color: var(--muted);
   font-size: 11px;
+  min-width: 0;
 }
-.primary-stat { display: inline-flex; align-items: baseline; gap: 4px; color: var(--text); }
+.video-card .video-stats {
+  flex-wrap: nowrap;
+  margin-top: auto;
+  padding-top: 8px;
+}
+.video-date {
+  flex: 0 0 auto;
+  color: var(--muted);
+  font-size: 12px;
+  white-space: nowrap;
+}
+.primary-stat { display: inline-flex; flex: 0 0 auto; align-items: baseline; gap: 4px; color: var(--text); white-space: nowrap; }
 .primary-stat b { font-size: 15px; font-weight: 600; }
 .primary-stat small { color: var(--muted); font-size: 11px; }
 .secondary-stat { white-space: nowrap; }
@@ -451,12 +505,13 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
 /* 统一的响应式媒体网格：移动端 2 列（图片自动缩放），PC 端 3 列。 */
 .media-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
 @media (min-width: 900px) { .media-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
-/* 统一的竖排媒体卡：图 + 两行截断标题 + 作者/数据行 + 高亮数据行。 */
+/* 竖排媒体卡：封面（时长）+ 两行标题 + 单行 UP + 日期/指标底栏。 */
 .media-card {
   position: relative;
   display: flex;
   flex-direction: column;
-  gap: 6px;
+  height: 100%;
+  gap: 8px;
   padding: 10px;
   border: 1px solid var(--border);
   border-radius: 16px;
@@ -468,33 +523,45 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
   background: color-mix(in srgb, var(--accent) 5%, var(--surface));
 }
-.media-rank {
-  position: absolute;
-  top: 10px;
-  left: 10px;
-  z-index: 1;
-  display: grid;
-  place-items: center;
-  width: 24px;
-  height: 24px;
-  border-radius: 6px;
-  background: rgba(0, 0, 0, 0.62);
-  color: #fff;
-  font-size: 11px;
-  font-weight: 600;
-}
 .media-thumb { width: 100%; aspect-ratio: 16 / 9; }
 .media-title {
   display: -webkit-box;
   -webkit-line-clamp: 2;
   -webkit-box-orient: vertical;
   overflow: hidden;
-  font-size: 13px;
-  line-height: 1.35;
+  font-size: 12px;
+  line-height: 1.4;
+  font-weight: 400;
+}
+.media-byline {
+  display: flex;
+  align-items: baseline;
+  justify-content: space-between;
+  gap: 8px;
+  min-width: 0;
+}
+.media-up {
+  min-width: 0;
+  flex: 1 1 auto;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: var(--muted);
+  font-size: 11px;
+}
+.media-date {
+  flex: 0 0 auto;
+  color: var(--muted);
+  font-size: 11px;
+  white-space: nowrap;
+}
+.media-highlight {
+  margin-top: auto;
+  color: var(--accent-strong);
+  font-size: 11px;
   font-weight: 600;
+  white-space: nowrap;
 }
-.media-meta { color: var(--muted); font-size: 11px; }
-.media-highlight { color: var(--accent-strong); font-size: 11px; font-weight: 600; }
 
 .status-grid {
   display: grid;
@@ -928,9 +995,7 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   .up-stats { grid-template-columns: repeat(5, minmax(0, 1fr)); }
   .detail-hero { flex-direction: row; align-items: flex-start; }
   .hero-cover { width: 300px; flex: 0 0 300px; }
-  .video-thumb { width: 112px; }
-  .video-card, .up-card { grid-template-columns: 24px 112px minmax(0, 1fr); }
-  .video-card.no-rank, .up-card.no-rank { grid-template-columns: 112px minmax(0, 1fr); }
+  .video-card { grid-template-columns: 144px minmax(0, 1fr); }
   .secondary-stat.optional { display: inline; }
 }
 
@@ -983,9 +1048,7 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
 }
 
 @media (max-width: 380px) {
-  .video-card, .up-card { grid-template-columns: 20px 80px minmax(0, 1fr); gap: 8px; }
-  .video-card.no-rank, .up-card.no-rank { grid-template-columns: 80px minmax(0, 1fr); }
-  .video-thumb { width: 80px; }
+  .video-card { grid-template-columns: 104px minmax(0, 1fr); gap: 8px; }
   .metric-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
   .candidate-card { grid-template-columns: 80px minmax(0, 1fr); }
   .candidate-thumb { width: 80px; }