/* cascade template — tangyunge.com — soft lavender-gray + charcoal */
:root {
  --bg: #e8e6ec;
  --bg-deep: #ddd9e3;
  --ink: #2a2d34;
  --ink-soft: #3d424c;
  --muted: #6b7080;
  --accent: #4a5568;
  --accent-soft: #6d7888;
  --lavender: #c8c4d4;
  --lavender-soft: #d9d5e0;
  --line: #c5c0ce;
  --soft: #f4f2f7;
  --card: rgba(244, 242, 247, 0.88);
  --max: 1080px;
  --zig-gap: clamp(3.5rem, 8vw, 6.5rem);
  --radius: 18px;
  --font-display: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink);
  background:
    radial-gradient(ellipse 90% 50% at 10% 0%, rgba(200, 196, 212, 0.55) 0%, transparent 55%),
    radial-gradient(ellipse 70% 40% at 90% 20%, rgba(170, 175, 190, 0.35) 0%, transparent 50%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-deep) 45%, #d4d0db 100%);
  background-attachment: fixed;
  line-height: 1.8;
  min-height: 100vh;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--ink); }

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ink);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 100;
}
.skip:focus { left: 0; }

/* —— chrome —— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(244, 242, 247, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.nav-row {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.7rem 1.15rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 650;
  font-size: 1.05rem;
  letter-spacing: 0.04em;
}
.brand img {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  object-fit: cover;
}

.menu-toggle {
  margin-left: auto;
  display: none;
  border: 1px solid var(--line);
  background: var(--soft);
  color: var(--ink);
  border-radius: 10px;
  padding: 0.45rem 0.85rem;
  font-size: 0.9rem;
  cursor: pointer;
}
.menu-toggle:hover { border-color: var(--accent-soft); }

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1.1rem;
  margin-left: auto;
}
.nav-links a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.92rem;
}
.nav-links a:hover { color: var(--ink); }

.ads-slot { max-width: var(--max); margin: 0 auto; }

/* —— cascade hero —— */
.cascade-hero {
  width: 100%;
  margin: 0;
  padding: 1.6rem 1.2rem 1.75rem;
  background:
    linear-gradient(105deg, #2f343e 0%, #3a4050 42%, #4a5160 100%);
  color: #f0eef4;
  border-bottom: 1px solid #1e222a;
}
.cascade-hero-inner {
  max-width: var(--max);
  margin: 0 auto;
}
.cascade-hero .eyebrow {
  display: inline-block;
  margin: 0 0 0.55rem;
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--lavender);
}
.cascade-hero h1 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3.2vw, 1.85rem);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: 0.02em;
}
.cascade-hero .lede {
  margin: 0;
  max-width: 42em;
  font-size: 0.98rem;
  color: #d4d0db;
  line-height: 1.7;
}

/* —— zig cascade —— */
.cascade-main {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.5rem 1.15rem 4rem;
}

.zig-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(1.5rem, 4vw, 2.75rem);
  align-items: center;
  margin: var(--zig-gap) 0;
  padding: 0;
}

.zig-section:nth-child(odd) .zig-text { order: 1; }
.zig-section:nth-child(odd) .zig-media { order: 2; }
.zig-section:nth-child(even) .zig-media { order: 1; }
.zig-section:nth-child(even) .zig-text { order: 2; }

.zig-text h2 {
  margin: 0 0 0.85rem;
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 2.4vw, 1.45rem);
  font-weight: 700;
  color: var(--ink);
  line-height: 1.35;
}
.zig-text p {
  margin: 0 0 0.85rem;
  color: var(--ink-soft);
  font-size: 0.98rem;
}
.zig-text p:last-child { margin-bottom: 0; }

.zig-media {
  margin: 0;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--soft);
  box-shadow: 0 18px 40px rgba(42, 45, 52, 0.08);
}
.zig-media img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}
.zig-media figcaption {
  padding: 0.55rem 0.85rem 0.7rem;
  font-size: 0.82rem;
  color: var(--muted);
  background: var(--card);
}

.cascade-prose {
  margin: var(--zig-gap) 0;
  padding: 1.6rem 1.4rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.cascade-prose h2 {
  margin: 0 0 0.9rem;
  font-family: var(--font-display);
  font-size: 1.3rem;
}
.cascade-prose p {
  margin: 0 0 0.9rem;
  color: var(--ink-soft);
}
.cascade-prose p:last-child { margin-bottom: 0; }

.cascade-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 1.25rem;
  margin: 1.25rem 0 0;
  padding-top: 1rem;
  border-top: 1px dashed var(--line);
}
.cascade-links a {
  color: var(--ink);
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid var(--lavender);
}
.cascade-links a:hover { border-color: var(--ink); }

.cascade-faq {
  margin: var(--zig-gap) 0 0;
}
.cascade-faq h2 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: 1.3rem;
}
.cascade-faq details {
  margin: 0 0 0.65rem;
  padding: 0.85rem 1rem;
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.cascade-faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--ink);
}
.cascade-faq details p {
  margin: 0.65rem 0 0;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* —— inner pages —— */
.page-main {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1.15rem 3.5rem;
}
.page-main h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: 1.55rem;
  color: var(--ink);
}
.page-main h2 {
  margin: 1.75rem 0 0.7rem;
  font-size: 1.15rem;
}
.page-main p,
.page-main li {
  color: var(--ink-soft);
  margin: 0 0 0.85rem;
}
.page-main ul { padding-left: 1.2rem; }

.err-box {
  text-align: center;
  padding-top: 3.5rem;
  padding-bottom: 4rem;
}
.err-box h1 { font-size: 1.7rem; }

.site-footer {
  border-top: 1px solid var(--line);
  background: rgba(47, 52, 62, 0.96);
  color: #c8c4d4;
  margin-top: 2rem;
}
.footer-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.25rem 1.15rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  justify-content: space-between;
  font-size: 0.88rem;
}
.site-footer a {
  color: #e0dce8;
  text-decoration: none;
}
.site-footer a:hover { color: #fff; }

@media (max-width: 820px) {
  .menu-toggle { display: inline-flex; align-items: center; }
  .nav-links {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    flex-direction: column;
    gap: 0;
    margin: 0;
    padding: 0.5rem 1.15rem 1rem;
    background: rgba(244, 242, 247, 0.98);
    border-bottom: 1px solid var(--line);
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    padding: 0.7rem 0;
    border-bottom: 1px solid var(--lavender-soft);
  }

  .zig-section {
    grid-template-columns: 1fr;
    gap: 1.15rem;
  }
  .zig-section:nth-child(odd) .zig-text,
  .zig-section:nth-child(odd) .zig-media,
  .zig-section:nth-child(even) .zig-text,
  .zig-section:nth-child(even) .zig-media {
    order: unset;
  }
  .zig-section:nth-child(even) .zig-media { order: -1; }
}