/* =========================================================
   夜羽凌・電子書書房 — styles.css
   設計方向：深夜靛藍 Hero + 溫暖米白內文 + 低調金色點綴
   襯線標題（文學感）+ 無襯線內文（易讀）。獨立作者書房，非模板感。
   ========================================================= */

/* ---------- 設計變數 ---------- */
:root {
  --ink:        #1d2333;
  --ink-soft:   #535b6e;
  --ink-faint:  #7b8294;
  --paper:      #fbf9f4;
  --paper-2:    #ffffff;
  --night-1:    #0d1130;
  --night-2:    #181d4a;
  --night-3:    #2a3173;
  --gold:       #c8a862;
  --gold-deep:  #a9863f;
  --line:       #e8e2d4;
  --line-soft:  #f0ebdf;

  --radius:     16px;
  --radius-sm:  10px;
  --shadow-sm:  0 1px 2px rgba(20,24,48,.06), 0 2px 6px rgba(20,24,48,.05);
  --shadow-md:  0 10px 30px rgba(20,24,48,.10), 0 2px 8px rgba(20,24,48,.06);
  --shadow-lg:  0 24px 60px rgba(13,17,48,.18);

  --maxw: 1120px;
  --font-serif: "Noto Serif TC", "Songti TC", "PingFang TC", "Microsoft JhengHei", serif;
  --font-sans:  "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", "Heiti TC", system-ui, -apple-system, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.75;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3, h4 { font-family: var(--font-serif); line-height: 1.3; letter-spacing: .01em; }

a { color: inherit; }

img { max-width: 100%; display: block; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.container-narrow { max-width: 760px; }

.section { padding: 84px 0; }

/* 區塊錨點偏移（避開固定頁首） */
:where(#books, #about, #faq, #disclosure, #top) { scroll-margin-top: 84px; }

.section-head { max-width: 640px; margin-bottom: 38px; }
.section-head h2 { font-size: clamp(1.7rem, 1.2rem + 1.8vw, 2.35rem); margin: .25em 0 .35em; }
.section-lede { color: var(--ink-soft); margin: 0; }

.eyebrow {
  font-size: .82rem; letter-spacing: .22em; text-transform: uppercase;
  color: var(--gold); font-weight: 700; margin: 0 0 .4em;
}
.eyebrow-dark { color: var(--gold-deep); }

/* 略過導覽連結 */
.skip-link {
  position: absolute; left: 16px; top: -60px; z-index: 200;
  background: var(--night-2); color: #fff; padding: 10px 16px;
  border-radius: 8px; text-decoration: none; transition: top .2s;
}
.skip-link:focus { top: 12px; }

/* ---------- 按鈕 ---------- */
.btn {
  --b: var(--night-2);
  display: inline-flex; align-items: center; justify-content: center; gap: .4em;
  font-family: var(--font-sans); font-size: 1rem; font-weight: 700;
  padding: 13px 26px; border-radius: 999px; border: 1.5px solid transparent;
  text-decoration: none; cursor: pointer; transition: transform .18s ease, box-shadow .18s ease, background .18s ease, color .18s ease, border-color .18s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-sm { padding: 9px 18px; font-size: .92rem; }
.btn-block { width: 100%; }

.btn-primary { background: var(--night-2); color: #fff; box-shadow: 0 8px 20px rgba(24,29,74,.22); }
.btn-primary:hover { background: #20276a; transform: translateY(-2px); box-shadow: 0 12px 26px rgba(24,29,74,.3); }

.btn-ghost { background: transparent; color: #fff; border-color: rgba(255,255,255,.5); }
.btn-ghost:hover { background: rgba(255,255,255,.1); border-color: #fff; transform: translateY(-2px); }

.btn-line { background: transparent; color: var(--ink); border-color: var(--line); }
.btn-line:hover { border-color: var(--gold); color: var(--gold-deep); background: #fffdf8; }

/* ---------- 頁首 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(251,249,244,.86);
  backdrop-filter: saturate(1.2) blur(10px);
  border-bottom: 1px solid var(--line-soft);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; min-height: 68px; }

.brand { display: inline-flex; align-items: baseline; gap: 8px; text-decoration: none; color: var(--ink); }
.brand-mark { color: var(--gold-deep); align-self: center; flex: none; }
.brand-name { font-family: var(--font-serif); font-weight: 900; font-size: 1.28rem; letter-spacing: .04em; }
.brand-sub { font-size: .82rem; color: var(--ink-faint); letter-spacing: .12em; }

.nav-links { display: flex; align-items: center; gap: 26px; }
.nav-links > a { text-decoration: none; font-size: .98rem; font-weight: 500; color: var(--ink-soft); transition: color .15s; }
.nav-links > a:hover { color: var(--ink); }
.nav-links > a.btn { color: #fff; }

.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; padding: 10px; cursor: pointer; }
.nav-toggle span { width: 24px; height: 2px; background: var(--ink); border-radius: 2px; transition: transform .25s, opacity .25s; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero { position: relative; color: #fff; overflow: hidden; isolation: isolate; }
.hero-bg {
  position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(1200px 520px at 78% -8%, rgba(110,120,220,.42), transparent 60%),
    radial-gradient(900px 480px at 6% 110%, rgba(200,168,98,.16), transparent 55%),
    linear-gradient(160deg, var(--night-1) 0%, var(--night-2) 58%, var(--night-3) 130%);
}
.hero-bg::after { /* 星點 */
  content: ""; position: absolute; inset: 0;
  background-image:
    radial-gradient(1.4px 1.4px at 20% 30%, rgba(255,255,255,.7), transparent),
    radial-gradient(1.2px 1.2px at 65% 18%, rgba(255,255,255,.55), transparent),
    radial-gradient(1.6px 1.6px at 82% 42%, rgba(255,255,255,.6), transparent),
    radial-gradient(1.2px 1.2px at 40% 60%, rgba(255,255,255,.45), transparent),
    radial-gradient(1.3px 1.3px at 90% 70%, rgba(255,255,255,.4), transparent),
    radial-gradient(1.2px 1.2px at 12% 75%, rgba(255,255,255,.4), transparent);
  opacity: .8;
}
.hero-inner {
  display: grid; grid-template-columns: 1.08fr .92fr; gap: 48px; align-items: center;
  padding: 92px 24px 96px;
}
.hero-copy { max-width: 600px; }
.hero h1 { font-size: clamp(2.05rem, 1.3rem + 3vw, 3.35rem); font-weight: 900; margin: .1em 0 .5em; }
.hero .lede { font-size: 1.12rem; color: rgba(255,255,255,.86); margin: 0 0 1.9em; }
.hero .lede strong { color: #fff; font-weight: 700; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 14px; }

.topic-chips { display: flex; flex-wrap: wrap; gap: 8px 10px; list-style: none; padding: 0; margin: 30px 0 0; }
.topic-chips li {
  font-size: .82rem; color: rgba(255,255,255,.82);
  border: 1px solid rgba(255,255,255,.25); border-radius: 999px; padding: 5px 13px;
}

/* Hero 書封扇形 */
.hero-visual { position: relative; height: 420px; }
.hero-cover {
  position: absolute; width: 210px; border-radius: 8px;
  box-shadow: var(--shadow-lg); border: 1px solid rgba(255,255,255,.14);
  transition: transform .4s cubic-bezier(.2,.7,.3,1);
}
.hero-cover.c1 { left: 4%;  top: 30px; transform: rotate(-9deg); z-index: 3; }
.hero-cover.c2 { left: 31%; top: 6px;  transform: rotate(0deg);  z-index: 2; width: 224px; }
.hero-cover.c3 { left: 60%; top: 34px; transform: rotate(9deg);  z-index: 1; }
.hero-visual:hover .c1 { transform: rotate(-13deg) translate(-10px,-6px); }
.hero-visual:hover .c3 { transform: rotate(13deg) translate(10px,-6px); }

/* ---------- 書籍區 ---------- */
.books { background: var(--paper); }

.filters { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 34px; }
.chip {
  font-family: var(--font-sans); font-size: .95rem; font-weight: 500;
  padding: 8px 18px; border-radius: 999px; cursor: pointer;
  background: #fff; color: var(--ink-soft); border: 1.5px solid var(--line);
  transition: all .18s ease;
}
.chip:hover { border-color: var(--gold); color: var(--ink); }
.chip.is-active { background: var(--night-2); color: #fff; border-color: var(--night-2); }

.book-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; align-items: start; }

.book-card {
  background: var(--paper-2); border: 1px solid var(--line-soft); border-radius: var(--radius);
  overflow: hidden; box-shadow: var(--shadow-sm);
  display: flex; flex-direction: column;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
.book-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); border-color: var(--line); }
.book-card[hidden] { display: none; }

.book-cover { background: linear-gradient(160deg,#eef0f6,#e4e7f1); padding: 26px 26px 0; display: flex; justify-content: center; }
.book-cover img { width: 64%; border-radius: 6px 6px 0 0; box-shadow: 0 12px 26px rgba(20,24,48,.22); }

.book-body { padding: 22px 24px 26px; display: flex; flex-direction: column; flex: 1; }
.tag { font-size: .76rem; letter-spacing: .04em; color: var(--gold-deep); font-weight: 700; }
.book-title { font-size: 1.28rem; font-weight: 700; margin: .35em 0 .5em; }
.book-subtitle { display: block; font-family: var(--font-sans); font-size: .9rem; font-weight: 500; color: var(--ink-faint); margin-top: 4px; }
.book-line { color: var(--ink-soft); font-size: .96rem; margin: 0 0 16px; }

.detail-toggle {
  align-self: flex-start; background: none; border: 0; padding: 4px 0;
  color: var(--ink); font-family: var(--font-sans); font-size: .92rem; font-weight: 700;
  cursor: pointer; border-bottom: 2px solid var(--gold); margin-bottom: 4px;
}
.detail-toggle::after { content: " ▾"; color: var(--gold-deep); }
.detail-toggle[aria-expanded="true"]::after { content: " ▴"; }
.detail-panel { padding: 6px 0 4px; border-top: 1px dashed var(--line); margin-top: 10px; }
.detail-panel h4 { font-family: var(--font-sans); font-size: .9rem; margin: 12px 0 6px; color: var(--ink); }
.detail-panel ul { margin: 0; padding-left: 1.15em; color: var(--ink-soft); font-size: .92rem; }
.detail-panel li { margin-bottom: 5px; }
.detail-panel p { margin: 0; color: var(--ink-soft); font-size: .92rem; }

.price-row { display: flex; align-items: baseline; gap: 10px; margin-top: auto; padding-top: 18px; }
.price-label { font-size: .82rem; color: #fff; background: var(--gold-deep); padding: 3px 10px; border-radius: 6px; font-weight: 700; }
.price { font-family: var(--font-serif); font-size: 1.5rem; font-weight: 700; color: var(--ink); }
.price-note { font-size: .78rem; color: var(--ink-faint); margin: 6px 0 16px; }

.buy-row { display: flex; flex-direction: column; gap: 10px; }

/* 購買通路說明 */
.channel-note {
  margin-top: 46px; background: #fff; border: 1px solid var(--line-soft);
  border-left: 4px solid var(--gold); border-radius: var(--radius-sm);
  padding: 22px 26px; box-shadow: var(--shadow-sm);
}
.channel-note h3 { font-size: 1.1rem; margin: 0 0 .4em; }
.channel-note p { margin: 0; color: var(--ink-soft); font-size: .96rem; }

/* ---------- 關於作者 ---------- */
.about { background: linear-gradient(180deg, #14193f 0%, #1b2150 100%); color: #fff; }
.about-inner { display: grid; grid-template-columns: 160px 1fr; gap: 44px; align-items: center; }
.about-mark { color: var(--gold); display: flex; justify-content: center; }
.about .eyebrow-dark { color: var(--gold); }
.about h2 { font-size: clamp(1.9rem,1.4rem+1.6vw,2.5rem); margin: .2em 0 .6em; }
.about-copy p { color: rgba(255,255,255,.84); margin: 0 0 1.1em; }
.about-topics { display: flex; flex-wrap: wrap; gap: 8px 10px; list-style: none; padding: 0; margin: 20px 0 0; }
.about-topics li { font-size: .84rem; border: 1px solid rgba(255,255,255,.28); border-radius: 999px; padding: 5px 14px; color: rgba(255,255,255,.9); }

/* ---------- FAQ ---------- */
.faq { background: var(--paper); }
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item { background: #fff; border: 1px solid var(--line-soft); border-radius: var(--radius-sm); box-shadow: var(--shadow-sm); overflow: hidden; }
.faq-q {
  width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 16px;
  background: none; border: 0; cursor: pointer; padding: 18px 22px; text-align: left;
  font-family: var(--font-sans); font-size: 1.04rem; font-weight: 700; color: var(--ink);
}
.faq-q:hover { color: var(--gold-deep); }
.faq-icon { position: relative; width: 16px; height: 16px; flex: none; }
.faq-icon::before, .faq-icon::after { content: ""; position: absolute; background: var(--gold-deep); border-radius: 2px; transition: transform .25s ease; }
.faq-icon::before { top: 7px; left: 0; width: 16px; height: 2px; }
.faq-icon::after  { left: 7px; top: 0; width: 2px; height: 16px; }
.faq-q[aria-expanded="true"] .faq-icon::after { transform: scaleY(0); }
.faq-a { padding: 0 22px 20px; }
.faq-a p { margin: 0; color: var(--ink-soft); }

/* ---------- 聯盟揭露 ---------- */
.disclosure { background: var(--paper); padding-top: 0; }
.disclosure-box {
  background: #fffdf6; border: 1px solid #efe6cf; border-radius: var(--radius);
  padding: 30px 34px; box-shadow: var(--shadow-sm);
}
.disclosure-box h2 { font-size: 1.25rem; margin: 0 0 .5em; }
.disclosure-box p { margin: 0; color: var(--ink-soft); }

/* ---------- 頁尾 ---------- */
.site-footer { background: var(--night-1); color: rgba(255,255,255,.72); padding: 52px 0 40px; }
.footer-inner { display: grid; grid-template-columns: 1.4fr 1fr 1.6fr; gap: 36px; }
.footer-brand .brand-name { color: #fff; font-size: 1.2rem; }
.footer-brand .brand-sub { color: var(--gold); margin-left: 6px; }
.footer-brand p { margin: 10px 0 0; font-size: .9rem; }
.footer-nav { display: flex; flex-direction: column; gap: 10px; }
.footer-nav a { text-decoration: none; color: rgba(255,255,255,.78); font-size: .94rem; }
.footer-nav a:hover { color: var(--gold); }
.footer-note p { margin: 0 0 8px; font-size: .84rem; line-height: 1.6; }
.footer-note .copyright { margin-top: 14px; color: rgba(255,255,255,.55); }

/* ---------- 進場動畫（尊重 reduced-motion）---------- */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------- RWD ---------- */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; gap: 12px; padding: 76px 24px 64px; text-align: left; }
  .hero-copy { max-width: 100%; }
  .hero-visual { height: 300px; margin-top: 8px; }
  .hero-cover { width: 158px; }
  .hero-cover.c2 { width: 168px; }
  .about-inner { grid-template-columns: 1fr; gap: 20px; text-align: left; }
  .about-mark { justify-content: flex-start; }
  .about-mark svg { width: 84px; height: 84px; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 760px) {
  .book-grid { grid-template-columns: repeat(2, 1fr); gap: 18px; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .section { padding: 60px 0; }
  .nav-links {
    position: fixed; inset: 68px 0 auto 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--paper); border-bottom: 1px solid var(--line);
    padding: 8px 24px 20px; box-shadow: var(--shadow-md);
    transform: translateY(-130%); transition: transform .28s ease; visibility: hidden;
  }
  .nav-links.is-open { transform: translateY(0); visibility: visible; }
  .nav-links > a { padding: 13px 4px; border-bottom: 1px solid var(--line-soft); }
  .nav-links > a.btn { margin-top: 12px; justify-content: center; }
  .nav-toggle { display: flex; }

  .hero-visual { height: 250px; }
  .hero-cover { width: 132px; }
  .hero-cover.c1 { left: 2%; }
  .hero-cover.c2 { width: 142px; left: 33%; }
  .hero-cover.c3 { left: 64%; }

  .book-grid { grid-template-columns: 1fr; gap: 18px; }
  .book-cover img { width: 52%; }
  .footer-inner { grid-template-columns: 1fr; gap: 26px; }
}

/* 小螢幕書封不要太高 */
@media (max-width: 420px) {
  .book-cover img { width: 58%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal { opacity: 1; transform: none; }
}