/* ============================================================================
   第 1 页：活动海报页
   仅保留：底图（.poster 承载 background-image）+ 向下滑动提示（.cover__hint）
   其余文字与装饰元素已移除，底图以原图铺满呈现。
   ========================================================================= */

/* 满屏海报：第 1 页不设安全距离，底图铺满整个视口 */
.cover {
  position: relative;
  height: 100%;
  padding: 0;
  /* 底部悬浮滑动提示：距底 + 高度，任何视口比例下位置稳定 */
  --hint-h: 51px;
  --hint-inset: clamp(20px, 3.6vh, 56px);
  --hint-gap: clamp(20px, 2.6vh, 40px);
  /* 底图未加载时的兜底色 */
  background: var(--bg-fallback);
  overflow: hidden;
}

/* 底图：cover 铺满 + 居中裁切。底图 1920×1078≈1.78，与 16:9 屏幕几乎 1:1 */
.poster {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg-fallback);
  background-image: var(--bg-image);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

/* ============================================================================
   居中品牌组合：logo 在上、主题在下方
   整体宽度 = 画面的 1/3，水平垂直居中叠在底图之上
   ========================================================================= */

.cover__brand {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, calc(-50% - 120px));
  z-index: 2;
  width: 33.333%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(14px, 2vh, 36px);
  pointer-events: none;   /* 不拦截底部的滑动提示交互 */
}

.cover__brand-logo {
  width: 44%;
  height: auto;
  display: block;
  /* 底图明暗变化大，给标志一层柔影保证轮廓清晰 */
  filter: drop-shadow(0 6px 20px rgba(48, 2, 0, 0.42));
}

.cover__brand-theme {
  width: 100%;
  height: auto;
  display: block;
  filter: drop-shadow(0 4px 16px rgba(48, 2, 0, 0.38));
}

/* ============================================================================
   底部滑动提示控件（点击 / 滚轮下滑 / 触摸上滑 / 键盘）
   ========================================================================= */

.cover__hint {
  /* 悬浮在海报底部中央：用 left/right + margin 居中，
     不占用 transform/translate，避免与浮动动画、hover 缩放互相覆盖 */
  position: absolute;
  left: 0;
  right: 0;
  bottom: var(--hint-inset);
  margin-inline: auto;
  width: fit-content;
  z-index: 3;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 9px 20px 9px 14px;
  border-radius: var(--r-pill);
  border: 1px solid rgba(255, 255, 255, 0.72);
  /* 白玻璃胶囊：底图底部是高亮地面光带，深红字刚好压住这块最亮处 */
  background: var(--hint-bg);
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  color: var(--hint-ink-2);
  cursor: pointer;
  user-select: none;
  transition:
    transform 320ms var(--ease-spring),
    background 260ms var(--ease-out),
    border-color 260ms var(--ease-out),
    box-shadow 260ms var(--ease-out);
  animation: hintFloat 2.8s var(--ease-io) infinite;
  box-shadow: 0 8px 26px rgba(60, 0, 0, 0.26), inset 0 1px 0 rgba(255, 255, 255, 0.9);
}

.cover__hint:hover {
  transform: translateY(-3px) scale(1.03);
  background: var(--hint-bg-2);
  border-color: #fff;
  box-shadow: 0 14px 38px rgba(60, 0, 0, 0.32), 0 0 0 6px rgba(255, 200, 90, 0.28),
    inset 0 1px 0 rgba(255, 255, 255, 0.95);
}

.cover__hint:active {
  transform: translateY(-1px) scale(0.99);
}

@keyframes hintFloat {
  0%, 100% { translate: 0 0; }
  50% { translate: 0 -6px; }
}

/* 鼠标图形 */
.hint-mouse {
  position: relative;
  width: 22px;
  height: 33px;
  border-radius: var(--r-pill);
  border: 1.6px solid var(--hint-line);
  flex: none;
}

.hint-mouse i {
  position: absolute;
  left: 50%;
  top: 6px;
  width: 3px;
  height: 6px;
  margin-left: -1.5px;
  border-radius: var(--r-pill);
  background: var(--hint-ink);
  box-shadow: 0 0 8px rgba(216, 31, 22, 0.55);
  animation: mouseWheel 1.9s var(--ease-io) infinite;
}

@keyframes mouseWheel {
  0% { opacity: 0; transform: translateY(-2px); }
  35% { opacity: 1; }
  70% { opacity: 1; transform: translateY(9px); }
  100% { opacity: 0; transform: translateY(12px); }
}

.hint-text {
  display: flex;
  flex-direction: column;
  line-height: 1.28;
  text-align: left;
}

.hint-text b {
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--hint-ink);
}

.hint-text span {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--hint-ink-2);
  text-transform: uppercase;
}

.hint-chev {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--gold-grad);
  color: var(--brand-3);
  flex: none;
  box-shadow: 0 3px 12px rgba(120, 60, 0, 0.4);
}

.hint-chev svg {
  animation: chevDrop 1.9s var(--ease-io) infinite;
}

@keyframes chevDrop {
  0%, 100% { transform: translateY(-2px); opacity: 0.72; }
  50% { transform: translateY(2px); opacity: 1; }
}