/**
 * @fileoverview 五一活动专题页样式。
 * 独立视觉：暖纸底、墨红强调、偏海报式排版，与首页区分且保持阅读清晰。
 */

:root {
  --paper: #f4f1ea;
  --paper-2: #ebe6dc;
  --ink: #1c1917;
  --ink-soft: #44403c;
  --red: #b91c1c;
  --red-deep: #7f1d1d;
  --gold: #b45309;
  --line: rgba(28, 25, 23, 0.12);
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "SF Mono", "Consolas", monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    repeating-linear-gradient(
      -12deg,
      transparent,
      transparent 11px,
      rgba(28, 25, 23, 0.03) 11px,
      rgba(28, 25, 23, 0.03) 12px
    );
  line-height: 1.65;
  min-height: 100vh;
}

a {
  color: var(--red-deep);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--red);
}

/* 顶栏 */
.act51-top {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  background: rgba(244, 241, 234, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.act51-top a.back {
  font-size: 0.875rem;
  color: var(--ink-soft);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.act51-top a.back:hover {
  color: var(--red);
}

.act51-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--red);
  border: 1px solid var(--red);
  padding: 0.2rem 0.5rem;
  text-transform: uppercase;
}

/* 主区域 */
.act51-wrap {
  max-width: 42rem;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}

.act51-hero {
  margin-bottom: 2.75rem;
  position: relative;
}

/* 角落大号水印，降低存在感 */
.act51-hero::before {
  content: "51";
  position: absolute;
  right: -0.5rem;
  top: -1.75rem;
  font-family: var(--font-mono);
  font-size: clamp(5rem, 22vw, 9rem);
  font-weight: 700;
  line-height: 1;
  color: rgba(185, 28, 28, 0.08);
  pointer-events: none;
  letter-spacing: -0.06em;
}

.act51-kicker {
  font-size: 0.8125rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.5rem;
}

.act51-title {
  font-size: clamp(1.75rem, 5.5vw, 2.35rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 1rem;
}

.act51-lead {
  margin: 0;
  font-size: 1.05rem;
  color: var(--ink-soft);
  max-width: 36ch;
}

/* 区块卡片 */
.act51-section {
  background: #fffef9;
  border: 1px solid var(--line);
  border-radius: 2px;
  padding: 1.35rem 1.35rem 1.5rem;
  margin-bottom: 1rem;
  box-shadow:
    0 1px 0 rgba(28, 25, 23, 0.06),
    0 8px 24px rgba(28, 25, 23, 0.06);
}

.act51-section h2 {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  margin: 0 0 0.85rem;
  padding-bottom: 0.6rem;
  border-bottom: 2px solid var(--ink);
  display: inline-block;
}

.act51-section p {
  margin: 0 0 0.65rem;
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.act51-section p:last-child {
  margin-bottom: 0;
}

/* 优惠码一行 */
.act51-code-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.65rem;
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  background: var(--paper-2);
  border: 1px dashed var(--line);
}

.act51-code {
  font-family: var(--font-mono);
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--red-deep);
}

.act51-copy {
  font-family: inherit;
  font-size: 0.8125rem;
  padding: 0.4rem 0.85rem;
  cursor: pointer;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: #fffef9;
  border-radius: 2px;
  letter-spacing: 0.06em;
}

.act51-copy:hover {
  background: var(--red-deep);
  border-color: var(--red-deep);
}

.act51-copy:active {
  transform: translateY(1px);
}

.act51-copy.copied {
  background: var(--gold);
  border-color: var(--gold);
}

/* 列表 */
.act51-list {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.act51-list li {
  margin-bottom: 0.35rem;
}

.act51-list li:last-child {
  margin-bottom: 0;
}

/* 抽奖外链入口 */
.act51-lottery-cta {
  margin: 1rem 0 0.75rem !important;
}

.act51-lottery-link {
  display: inline-block;
  padding: 0.55rem 1.15rem;
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: #fffef9 !important;
  text-decoration: none !important;
  background: var(--red);
  border-radius: 2px;
  border: 1px solid var(--red-deep);
  box-shadow:
    0 1px 0 rgba(28, 25, 23, 0.08),
    0 4px 12px rgba(185, 28, 28, 0.25);
}

.act51-lottery-link:hover {
  background: var(--red-deep);
  border-color: var(--ink);
  color: #fffef9 !important;
}

.act51-lottery-link:active {
  transform: translateY(1px);
  box-shadow: 0 2px 6px rgba(185, 28, 28, 0.2);
}

.act51-note {
  margin-top: 0.85rem !important;
  font-size: 0.8125rem !important;
  color: #78716c !important;
  border-left: 3px solid var(--gold);
  padding-left: 0.65rem;
}

.act51-foot {
  margin-top: 2.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  font-size: 0.8125rem;
  color: #78716c;
  text-align: center;
}

@media (min-width: 640px) {
  .act51-wrap {
    padding-top: 3.25rem;
  }

  .act51-section {
    padding: 1.5rem 1.65rem 1.65rem;
  }
}