/* books.rikka.moe — 极简手写样式（无框架、无构建）。
   设计原则：一栏阅读流、一个墨色 + 一个购买强调色、超大可点按钮、
   最少的装饰；让只会点按钮的读者也能完成「下载 → 解压 → 阅读」。 */

:root {
  --ink: #1c1e21;
  --ink-soft: #565c66;
  --paper: #ffffff;
  --paper-dim: #f6f6f4;
  --line: #e6e6e2;
  --accent: #1f5af5;      /* 免费下载：冷静的蓝 */
  --accent-ink: #ffffff;
  --buy: #d4491f;         /* 购买强调：温暖的橙红 */
  --buy-ink: #ffffff;
  --ok: #1a7f4b;
  --err: #b3261e;
  --radius: 14px;
  --maxw: 46rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e8e8e6;
    --ink-soft: #9aa0a8;
    --paper: #141517;
    --paper-dim: #1d1f22;
    --line: #2b2e33;
    --accent: #6c93ff;
    --accent-ink: #0c1220;
    --buy: #ff7a4d;
    --buy-ink: #1c1008;
    --ok: #5ec98d;
    --err: #ff8a80;
  }
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "PingFang SC", "Noto Sans SC",
    "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.75;
  font-size: 17px;
}

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.topbar .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 3.5rem;
}
.brand {
  font-weight: 700;
  text-decoration: none;
  color: var(--ink);
  letter-spacing: 0.02em;
}
.topnav { display: flex; gap: 0.75rem; }
.topnav a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.95rem;
  padding: 0.35rem 0.1rem;
}
.topnav a:hover { color: var(--ink); }

/* ---------- 首屏 ---------- */
.hero { padding: 4.5rem 0 3.5rem; text-align: center; }
.kicker {
  color: var(--ink-soft);
  font-size: 0.9rem;
  letter-spacing: 0.35em;
  margin: 0 0 1.2rem;
}
.hero h1 {
  font-size: clamp(2.2rem, 7vw, 3.4rem);
  line-height: 1.25;
  margin: 0 0 1rem;
  letter-spacing: 0.04em;
}
.hero .sub {
  color: var(--ink-soft);
  max-width: 34rem;
  margin: 0 auto 2.5rem;
  font-size: 1.05rem;
}
.hero-cover {
  width: 168px;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 12px 40px rgb(0 0 0 / 0.18);
  margin: 0 auto 2.5rem;
  display: block;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  min-height: 3.25rem;
  padding: 0.7rem 1.6rem;
  border-radius: 999px;
  font-size: 1.1rem;
  font-weight: 700;
  text-decoration: none;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.06s ease, filter 0.15s ease;
}
.btn:active { transform: scale(0.98); }
.btn--primary { background: var(--accent); color: var(--accent-ink); }
.btn--buy { background: var(--buy); color: var(--buy-ink); }
.btn--ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}
.btn:hover { filter: brightness(1.06); }
.btn .arrow { font-size: 1.2em; line-height: 1; }

.hero-cta { display: flex; flex-wrap: wrap; gap: 0.9rem; justify-content: center; }

/* ---------- 三步指引 ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 0 0 4.5rem;
}
.step { background: var(--paper); padding: 1.4rem 1.2rem; text-align: center; }
.step .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 50%;
  background: var(--paper-dim);
  font-weight: 800;
  margin-bottom: 0.6rem;
}
.step h3 { margin: 0 0 0.3rem; font-size: 1.02rem; }
.step p { margin: 0; color: var(--ink-soft); font-size: 0.9rem; line-height: 1.6; }
@media (max-width: 640px) {
  .steps { grid-template-columns: 1fr; }
}

/* ---------- 区块 ---------- */
section { padding: 2.5rem 0 3.5rem; }
section + section { border-top: 1px solid var(--line); }
.sec-head { margin-bottom: 1.8rem; }
.sec-head h2 {
  font-size: 1.7rem;
  margin: 0 0 0.5rem;
  letter-spacing: 0.03em;
}
.sec-head p { color: var(--ink-soft); margin: 0; }
.anchor { scroll-margin-top: 4.5rem; }

/* ---------- 免费下载列表 ---------- */
.dl-list { display: flex; flex-direction: column; gap: 0.8rem; }
.dl-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.05rem 1.4rem;
  border: 2px solid var(--accent);
  border-radius: var(--radius);
  color: var(--accent);
  font-size: 1.15rem;
  font-weight: 700;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease;
}
.dl-item:hover { background: var(--accent); color: var(--accent-ink); }
.dl-item .dl-arrow { font-size: 1.35em; line-height: 1; }
.dl-item small {
  display: block;
  font-size: 0.85rem;
  font-weight: 400;
  color: inherit;
  opacity: 0.75;
}
.dl-item--zip { border-color: var(--ink-soft); color: var(--ink); }
.dl-item--zip:hover { background: var(--ink-soft); color: var(--paper); }
.dl-note { color: var(--ink-soft); font-size: 0.95rem; margin: 1.1rem 0 0; }

/* ---------- 购买区 ---------- */
.buy-box {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 2rem 1.6rem;
  background: var(--paper-dim);
}
.buy-box .pitch {
  font-size: 1.12rem;
  margin: 0 0 1.6rem;
}
.buy-box .pitch strong { color: var(--buy); }
.buy-steps { margin: 0 0 1.8rem; padding: 0; counter-reset: buystep; list-style: none; }
.buy-steps li {
  counter-increment: buystep;
  position: relative;
  padding: 0 0 1.1rem 2.6rem;
}
.buy-steps li::before {
  content: counter(buystep);
  position: absolute;
  left: 0;
  top: 0.1rem;
  width: 1.7rem;
  height: 1.7rem;
  border-radius: 50%;
  background: var(--buy);
  color: var(--buy-ink);
  font-weight: 800;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: center;
}
.buy-actions { display: flex; flex-wrap: wrap; gap: 0.9rem; margin: 0 0 2rem; }

/* 密钥表单（沿用原 id，配合 assets/site.js） */
.dl-form { display: flex; gap: 0.7rem; flex-wrap: wrap; }
.dl-input {
  flex: 1 1 14rem;
  min-height: 3.25rem;
  padding: 0.6rem 1.1rem;
  font-size: 1.05rem;
  font-family: inherit;
  color: var(--ink);
  background: var(--paper);
  border: 2px solid var(--line);
  border-radius: var(--radius);
}
.dl-input:focus { outline: 3px solid color-mix(in srgb, var(--accent) 35%, transparent); border-color: var(--accent); }
.dl-btn {
  min-height: 3.25rem;
  padding: 0.6rem 1.8rem;
  font-size: 1.05rem;
  font-weight: 700;
  font-family: inherit;
  color: var(--accent-ink);
  background: var(--accent);
  border: 0;
  border-radius: var(--radius);
  cursor: pointer;
}
.dl-btn:disabled { opacity: 0.6; cursor: wait; }
.dl-status { min-height: 1.6rem; margin: 0.9rem 0 0; font-size: 0.98rem; }
.dl-status--ok { color: var(--ok); font-weight: 600; }
.dl-status--error { color: var(--err); font-weight: 600; }
.dl-hidden { display: none; }

/* 验证成功后的下载按钮 */
#premium-results .dl-item { border-color: var(--buy); color: var(--buy); }
#premium-results .dl-item:hover { background: var(--buy); color: var(--buy-ink); }

/* ---------- 帮助中心 ---------- */
.help-block { margin-bottom: 2.2rem; }
.help-block h3 {
  font-size: 1.25rem;
  margin: 0 0 0.9rem;
}
.help-block ul { margin: 0; padding: 0; list-style: none; }
.help-block li {
  padding: 0.85rem 0;
  border-top: 1px dashed var(--line);
}
.help-block li:first-child { border-top: 0; }
.help-block .os {
  display: inline-block;
  min-width: 6.2rem;
  font-weight: 700;
}
.help-block li p { margin: 0.15rem 0 0; color: var(--ink-soft); font-size: 0.93rem; }

.callout {
  border-left: 4px solid var(--accent);
  background: var(--paper-dim);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.3rem;
  margin: 1.5rem 0 0;
}
.callout p { margin: 0; font-size: 0.98rem; }
.callout strong { color: var(--accent); }

/* ---------- 内容预览（书页截图） ---------- */
.sub-head {
  font-size: 1.05rem;
  margin: 2.2rem 0 0.9rem;
  letter-spacing: 0.02em;
}
.previews {
  display: flex;
  gap: 0.85rem;
  overflow-x: auto;
  padding: 0.15rem 0.15rem 0.6rem;
  margin: 0 -0.15rem;
  scroll-snap-type: x proximity;
}
.previews figure {
  margin: 0;
  flex: 0 0 auto;
  scroll-snap-align: start;
  text-align: center;
}
.previews a {
  display: block;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  line-height: 0;
  transition: border-color 0.15s ease;
}
.previews a:hover { border-color: var(--accent); }
.previews img {
  display: block;
  height: 216px;
  width: auto;
}
.previews figcaption {
  margin-top: 0.4rem;
  font-size: 0.8rem;
  line-height: 1.4;
  color: var(--ink-soft);
}
.previews--sm img { height: 132px; }
@media (max-width: 640px) {
  .previews img { height: 168px; }
  .previews--sm img { height: 110px; }
}

/* ---------- 其他书目 ---------- */
/* minmax(0,1fr)：auto 列会被卡内横向滚动的截图撑破容器 */
.minor-books { display: grid; gap: 1rem; grid-template-columns: minmax(0, 1fr); }
.minor-book {
  display: flex;
  gap: 1.1rem;
  align-items: flex-start;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.2rem 1.3rem;
}
.minor-book > img {
  width: 64px;
  height: auto;
  border-radius: 4px;
  flex-shrink: 0;
}
/* flex 子项默认 min-width:auto，会把内部横向滚动条撑破容器 → 显式归零 */
.minor-book > div { min-width: 0; flex: 1 1 auto; }
.minor-book h3 { margin: 0 0 0.25rem; font-size: 1.05rem; }
.minor-book p { margin: 0; color: var(--ink-soft); font-size: 0.92rem; }
.tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--ink-soft);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.05rem 0.6rem;
  margin-left: 0.4rem;
  vertical-align: 2px;
}

/* ---------- 页脚 ---------- */
footer { border-top: 1px solid var(--line); padding: 2.2rem 0 3rem; }
footer .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1.4rem;
  justify-content: center;
  color: var(--ink-soft);
  font-size: 0.9rem;
}
footer a { color: var(--ink-soft); text-decoration: none; }
footer a:hover { color: var(--ink); }

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}