/* ============================================================
   YUKI138 — 瀑布流 masonry 骨架（折纸蓝灰 / 纸白蓝）
   类名一律 yk- 前缀；首屏零位图（鹤形/折痕/步骤条全 CSS）
   ============================================================ */

:root {
  --yk-bg: #1A1F27;
  --yk-bg2: #20262F;
  --yk-bg3: #232A35;
  --yk-paper: #DCE8F5;
  --yk-shadow: #8FB8E8;
  --yk-tx: #E9EEF6;
  --yk-tx2: #A3AEC2;
  --yk-line: #303947;
  --yk-gold: #F2C94C;
  --yk-disp: "Dela Gothic One", system-ui, sans-serif;
  --yk-body: "Zen Kaku Gothic New", "Segoe UI", system-ui, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--yk-body);
  background:
    radial-gradient(1100px 500px at 85% -5%, rgba(143, 184, 232, .10), transparent 60%),
    radial-gradient(800px 420px at -10% 30%, rgba(220, 232, 245, .05), transparent 55%),
    var(--yk-bg);
  color: var(--yk-tx);
  line-height: 1.75;
  font-size: 16px;
  overflow-x: hidden;
}

a { color: var(--yk-paper); text-decoration: none; }
a:hover { color: #ffffff; }
img { max-width: 100%; height: auto; display: block; }

h1, h2, h3 { font-family: var(--yk-disp); font-weight: 400; line-height: 1.28; letter-spacing: .3px; }
h1 { font-size: clamp(1.65rem, 3.6vw, 2.5rem); }
h2 { font-size: clamp(1.3rem, 2.6vw, 1.8rem); margin-bottom: 14px; }
h3 { font-size: 1.02rem; line-height: 1.5; }

::selection { background: var(--yk-shadow); color: #10141b; }

/* ---------------- 头部 ---------------- */

.yk-head {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(26, 31, 39, .92);
  backdrop-filter: blur(9px);
  border-bottom: 1px solid var(--yk-line);
}

.yk-headin {
  max-width: 1200px;
  margin: 0 auto;
  padding: 12px 22px;
  display: flex;
  align-items: center;
  gap: 22px;
}

.yk-logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }

.yk-logo-fold { display: inline-flex; width: 36px; height: 30px; position: relative; }
.yk-logo-fold i {
  position: absolute;
  background: linear-gradient(135deg, var(--yk-paper), var(--yk-shadow));
  box-shadow: 0 0 10px rgba(143, 184, 232, .5);
}
.yk-logo-fold i:nth-child(1) { width: 20px; height: 20px; clip-path: polygon(50% 0, 100% 100%, 0 100%); left: 0; top: 2px; }
.yk-logo-fold i:nth-child(2) { width: 16px; height: 16px; clip-path: polygon(50% 0, 100% 100%, 0 100%); right: 0; bottom: 0; opacity: .7; }
.yk-logo-fold i:nth-child(3) { width: 10px; height: 10px; transform: rotate(45deg); right: 8px; top: 0; opacity: .9; }

.yk-logo-word { font-family: var(--yk-disp); font-size: 1.12rem; letter-spacing: .5px; color: var(--yk-tx); }

.yk-nav { display: flex; gap: 20px; margin-left: auto; font-size: .93rem; }
.yk-nav a { color: var(--yk-tx2); padding: 6px 2px; border-bottom: 2px solid transparent; }
.yk-nav a:hover, .yk-nav .yk-on { color: var(--yk-paper); border-bottom-color: var(--yk-shadow); }

.yk-hact { display: flex; gap: 10px; flex-shrink: 0; }

.yk-btn {
  display: inline-block;
  font-family: var(--yk-body);
  font-weight: 700;
  font-size: .92rem;
  padding: 9px 20px;
  border-radius: 4px;
  transition: transform .15s ease, box-shadow .15s ease;
  cursor: pointer;
}
.yk-btn-fill {
  background: linear-gradient(160deg, var(--yk-paper), #b9cfe8 70%);
  color: #17202c;
  box-shadow: 0 0 0 1px rgba(220, 232, 245, .25), 0 4px 18px rgba(143, 184, 232, .28);
}
.yk-btn-fill:hover { transform: translateY(-1px); box-shadow: 0 6px 24px rgba(143, 184, 232, .45); color: #17202c; }
.yk-btn-line {
  border: 1px solid var(--yk-shadow);
  color: var(--yk-paper);
  background: rgba(143, 184, 232, .06);
}
.yk-btn-line:hover { background: rgba(143, 184, 232, .16); color: #ffffff; }

.yk-burger { display: none; margin-left: auto; cursor: pointer; width: 42px; }
.yk-burger span { display: block; height: 2px; margin: 5px 0; background: var(--yk-paper); border-radius: 2px; transition: .2s; }

.yk-navtog { display: none; }
.yk-mnav { display: none; }

/* ---------------- 主体容器 ---------------- */

.yk-main { max-width: 1200px; margin: 0 auto; padding: 0 22px; }

/* ---------------- hero：折纸鹤 ---------------- */

.yk-hero { padding: 54px 0 8px; }

.yk-herogrid {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: 34px;
  align-items: center;
}

.yk-kicker {
  display: inline-block;
  font-size: .78rem;
  letter-spacing: 1.6px;
  text-transform: uppercase;
  color: var(--yk-shadow);
  border: 1px dashed rgba(143, 184, 232, .55);
  padding: 4px 12px;
  margin-bottom: 16px;
  border-radius: 3px;
}

.yk-hero .yk-lede { color: var(--yk-tx2); margin: 16px 0 24px; max-width: 620px; }

.yk-heroact { display: flex; gap: 12px; flex-wrap: wrap; }

.yk-cranewrap { position: relative; height: 300px; }

.yk-crane { position: absolute; inset: 0 12% 12% 12%; }

.yk-crane span { position: absolute; }

.yk-wing {
  top: 34%;
  width: 46%;
  height: 34%;
  background: linear-gradient(120deg, #f2f7fd 0%, var(--yk-paper) 45%, var(--yk-shadow) 100%);
  filter: drop-shadow(0 0 14px rgba(143, 184, 232, .38));
}
.yk-wing-l { left: 4%; clip-path: polygon(100% 88%, 0 30%, 62% 0); transform: rotate(-4deg); }
.yk-wing-r { right: 4%; clip-path: polygon(0 88%, 100% 30%, 38% 0); transform: rotate(4deg) scaleX(-1); }

.yk-neck {
  top: 6%;
  left: 50%;
  width: 17%;
  height: 42%;
  transform: translateX(-50%) rotate(12deg);
  clip-path: polygon(38% 0, 62% 14%, 70% 100%, 24% 100%);
  background: linear-gradient(160deg, #eef4fb, var(--yk-shadow) 90%);
  filter: drop-shadow(0 0 10px rgba(143, 184, 232, .3));
}

.yk-tail {
  top: 24%;
  left: 8%;
  width: 30%;
  height: 26%;
  clip-path: polygon(0 0, 100% 74%, 8% 100%);
  background: linear-gradient(200deg, #e7eefa, #a8c4e4);
  opacity: .92;
}

.yk-base {
  bottom: 8%;
  left: 50%;
  width: 58%;
  height: 24%;
  transform: translateX(-50%);
  clip-path: polygon(50% 0, 100% 100%, 0 100%);
  background: linear-gradient(180deg, var(--yk-paper), #7fa6d4);
  filter: drop-shadow(0 10px 18px rgba(0, 0, 0, .45));
}

.yk-creasefield {
  position: absolute;
  inset: auto 0 0 0;
  height: 120px;
  background:
    repeating-linear-gradient(72deg, transparent 0 34px, rgba(220, 232, 245, .08) 34px 36px),
    repeating-linear-gradient(-64deg, transparent 0 46px, rgba(143, 184, 232, .10) 46px 48px);
  mask-image: linear-gradient(180deg, transparent, #000 55%, transparent);
}

.yk-fsteps {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-top: 30px;
}

.yk-fstep {
  position: relative;
  border: 1px solid var(--yk-line);
  border-top: 2px solid var(--yk-shadow);
  background: linear-gradient(178deg, var(--yk-bg2), var(--yk-bg));
  padding: 14px 14px 12px;
  box-shadow: inset 0 12px 22px -18px rgba(143, 184, 232, .55);
}
.yk-fstep h3 { margin: 6px 0 4px; }
.yk-fstep p { font-size: .84rem; color: var(--yk-tx2); }

.yk-fno {
  font-family: var(--yk-disp);
  font-size: .8rem;
  color: var(--yk-shadow);
  text-shadow: 0 0 12px rgba(143, 184, 232, .8);
}

/* ---------------- 折痕线（中奖线意象）分隔 ---------------- */

.yk-payline {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: 40px auto;
  max-width: 1160px;
  color: rgba(143, 184, 232, .8);
  text-shadow: 0 0 10px rgba(143, 184, 232, .6);
}
.yk-payline::before, .yk-payline::after {
  content: "";
  flex: 1;
  border-top: 1px dashed rgba(143, 184, 232, .45);
  margin: 0 14px;
}

/* ---------------- masonry 步骤墙（Tangga Lipatan） ---------------- */

.yk-wall { padding: 18px 0 8px; }

.yk-wallp { color: var(--yk-tx2); max-width: 740px; margin-bottom: 26px; }

.yk-mason { columns: 3; column-gap: 16px; }

.yk-card {
  break-inside: avoid;
  margin: 0 0 16px;
  border: 1px solid var(--yk-line);
  border-radius: 6px;
  background: linear-gradient(176deg, var(--yk-bg2), var(--yk-bg3) 130%);
  padding: 18px 16px 16px;
  position: relative;
  overflow: hidden;
  transition: border-color .18s ease, box-shadow .18s ease;
}
.yk-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 26px;
  background:
    repeating-linear-gradient(90deg, rgba(143, 184, 232, .16) 0 2px, transparent 2px 26px),
    linear-gradient(180deg, rgba(143, 184, 232, .10), transparent);
}
.yk-card:hover { border-color: var(--yk-shadow); box-shadow: 0 6px 26px rgba(143, 184, 232, .16); }

.yk-card h3 { margin: 10px 0 8px; }
.yk-card h3 a { color: var(--yk-paper); }
.yk-card h3 a:hover { text-decoration: underline; text-decoration-color: var(--yk-shadow); }
.yk-card p { font-size: .92rem; color: var(--yk-tx2); }

.yk-card-edu { padding-top: 26px; }

.yk-stage {
  position: absolute;
  top: 30px;
  right: 12px;
  font-size: .68rem;
  letter-spacing: 1.4px;
  text-transform: uppercase;
  color: var(--yk-shadow);
  border: 1px solid rgba(143, 184, 232, .4);
  padding: 2px 8px;
  border-radius: 2px;
  background: rgba(26, 31, 39, .7);
}
.yk-stage-pick { color: var(--yk-gold); border-color: rgba(242, 201, 76, .45); }
.yk-stage-note { color: var(--yk-paper); }

.yk-card-note { background: linear-gradient(176deg, #1d232c, #26303d); border-style: dashed; }
.yk-card-note::before { opacity: .35; }
.yk-card-note p { color: var(--yk-tx); }

.yk-more {
  display: inline-block;
  margin-top: 10px;
  font-size: .85rem;
  font-weight: 700;
  color: var(--yk-shadow);
}
.yk-more:hover { color: var(--yk-paper); }

/* ---------------- 叙述区 ---------------- */

.yk-tell { padding: 34px 0 10px; }
.yk-tell p { color: var(--yk-tx2); margin-bottom: 14px; max-width: 820px; }

.yk-herofig { margin: 26px 0 30px; border: 1px solid var(--yk-line); border-radius: 8px; overflow: hidden; }
.yk-herofig img { width: 100%; }
.yk-herofig figcaption { font-size: .82rem; color: var(--yk-tx2); padding: 10px 16px; border-top: 1px dashed rgba(143, 184, 232, .35); background: rgba(32, 38, 47, .6); }

.yk-edges { list-style: none; display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-top: 18px; }
.yk-edges li {
  border-left: 3px solid var(--yk-shadow);
  background: linear-gradient(90deg, rgba(143, 184, 232, .08), transparent 70%);
  padding: 12px 16px;
}
.yk-edges h3 { color: var(--yk-paper); margin-bottom: 4px; }
.yk-edges p { font-size: .9rem; color: var(--yk-tx2); margin: 0; }

/* ---------------- FAQ / 信任 ---------------- */

.yk-faqsec { padding: 30px 0 10px; }
.yk-q { border: 1px solid var(--yk-line); border-radius: 5px; background: var(--yk-bg2); margin-bottom: 10px; }
.yk-q summary {
  cursor: pointer;
  list-style: none;
  font-weight: 700;
  padding: 14px 18px;
  position: relative;
  padding-right: 44px;
}
.yk-q summary::-webkit-details-marker { display: none; }
.yk-q summary::after {
  content: "\2666";
  position: absolute;
  right: 18px;
  top: 12px;
  color: var(--yk-shadow);
  transform: rotate(0deg);
  transition: transform .2s ease;
}
.yk-q[open] summary::after { transform: rotate(90deg); }
.yk-q p { padding: 0 18px 14px; color: var(--yk-tx2); font-size: .95rem; }

.yk-trust {
  margin: 34px 0 26px;
  border: 1px solid rgba(242, 201, 76, .35);
  border-radius: 8px;
  background: linear-gradient(170deg, rgba(242, 201, 76, .07), rgba(143, 184, 232, .05));
  padding: 24px 26px;
}
.yk-trust h2 { color: var(--yk-gold); }
.yk-trust p { color: var(--yk-tx2); max-width: 860px; }
.yk-trustlnk { display: inline-block; margin-top: 12px; font-weight: 700; color: var(--yk-gold); }

/* ---------------- 文章纸面 ---------------- */

.yk-paper { max-width: 880px; margin: 0 auto; padding: 30px 22px 46px; }

.yk-crumbs { font-size: .82rem; color: var(--yk-tx2); margin-bottom: 18px; }
.yk-crumbs a { color: var(--yk-shadow); }
.yk-crumbs span { color: var(--yk-tx2); }

.yk-navintro, .yk-edulead { font-size: 1.05rem; color: var(--yk-tx2); margin-bottom: 22px; }

.yk-steps { list-style: none; counter-reset: ykstep; margin-bottom: 22px; }
.yk-steps li {
  counter-increment: ykstep;
  position: relative;
  padding: 14px 16px 14px 58px;
  border: 1px solid var(--yk-line);
  border-radius: 5px;
  margin-bottom: 10px;
  background: var(--yk-bg2);
}
.yk-steps li::before {
  content: "\2666 " counter(ykstep);
  position: absolute;
  left: 14px;
  top: 15px;
  font-size: .82rem;
  color: var(--yk-shadow);
  text-shadow: 0 0 10px rgba(143, 184, 232, .6);
}
.yk-steps h3 { margin-bottom: 3px; }
.yk-steps p { color: var(--yk-tx2); font-size: .94rem; }

.yk-navlist { list-style: none; margin-bottom: 22px; }
.yk-navlist li { padding: 9px 0 9px 26px; border-bottom: 1px dashed rgba(143, 184, 232, .25); position: relative; color: var(--yk-tx2); }
.yk-navlist li::before { content: "\2666"; position: absolute; left: 2px; color: var(--yk-shadow); }
.yk-navlist b { color: var(--yk-paper); }

.yk-note {
  border-left: 3px solid var(--yk-gold);
  background: rgba(242, 201, 76, .06);
  padding: 12px 16px;
  font-size: .95rem;
  color: var(--yk-tx2);
  margin-bottom: 24px;
}

.yk-rel {
  border: 1px solid var(--yk-line);
  border-radius: 6px;
  background: var(--yk-bg2);
  padding: 16px 18px;
  margin: 24px 0;
}
.yk-rel h3 { font-family: var(--yk-body); font-weight: 700; font-size: .8rem; letter-spacing: 1.6px; text-transform: uppercase; color: var(--yk-shadow); margin: 8px 0 6px; }
.yk-rel h3:first-child { margin-top: 0; }
.yk-rel a { display: block; padding: 5px 0; color: var(--yk-tx2); font-size: .94rem; }
.yk-rel a:hover { color: var(--yk-paper); }

.yk-edu h2 { margin-top: 30px; }
.yk-edu p { color: var(--yk-tx2); margin-bottom: 14px; }

.yk-fig { margin: 24px 0; border: 1px solid var(--yk-line); border-radius: 8px; overflow: hidden; }
.yk-fig img { width: 100%; }
.yk-fig figcaption { font-size: .82rem; color: var(--yk-tx2); padding: 9px 14px; border-top: 1px dashed rgba(143, 184, 232, .35); background: rgba(32, 38, 47, .6); }

.yk-resp {
  margin-top: 26px;
  font-size: .84rem;
  color: var(--yk-tx2);
  border-top: 1px dashed rgba(242, 201, 76, .4);
  padding-top: 14px;
}

/* ---------------- 404 ---------------- */

.yk-404body { background: var(--yk-bg); }
.yk-404 { max-width: 720px; margin: 0 auto; padding: 70px 22px 90px; text-align: center; }
.yk-404fold { font-size: 1rem; letter-spacing: 6px; color: var(--yk-shadow); margin-bottom: 18px; text-shadow: 0 0 14px rgba(143, 184, 232, .7); }
.yk-404fold span:nth-child(2) { font-family: var(--yk-disp); font-size: 2.6rem; margin: 0 10px; }
.yk-404 p { color: var(--yk-tx2); margin: 14px 0 26px; }
.yk-404act { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* ---------------- 页脚 ---------------- */

.yk-foot { border-top: 1px solid var(--yk-line); background: #161a21; margin-top: 30px; }

.yk-fgrid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 38px 22px 20px;
  display: grid;
  grid-template-columns: 2fr 1fr 1.4fr 1fr;
  gap: 26px;
}

.yk-fbrand p { font-size: .86rem; color: var(--yk-tx2); margin: 12px 0; }

.yk-18 {
  display: inline-block;
  border: 2px solid var(--yk-gold);
  color: var(--yk-gold);
  font-weight: 700;
  border-radius: 50%;
  width: 42px;
  height: 42px;
  line-height: 38px;
  text-align: center;
}

.yk-fcol h3 { font-family: var(--yk-body); font-size: .8rem; letter-spacing: 1.6px; text-transform: uppercase; color: var(--yk-shadow); margin-bottom: 10px; }
.yk-fcol a { display: block; color: var(--yk-tx2); font-size: .9rem; padding: 3px 0; }
.yk-fcol a:hover { color: var(--yk-paper); }

.yk-fbot { border-top: 1px solid var(--yk-line); padding: 14px 22px 18px; text-align: center; }
.yk-fbot p { font-size: .8rem; color: var(--yk-tx2); }

/* ---------------- 底部悬浮条（唯一外链） ---------------- */

.yk-float {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 80;
  display: flex;
  justify-content: center;
  padding: 8px 12px calc(8px + env(safe-area-inset-bottom));
  background: linear-gradient(180deg, rgba(26, 31, 39, 0), rgba(22, 26, 33, .96) 40%);
  pointer-events: none;
}
.yk-floatin {
  pointer-events: auto;
  display: flex;
  align-items: center;
  gap: 16px;
  border: 1px solid rgba(143, 184, 232, .4);
  background: rgba(32, 38, 47, .95);
  border-radius: 40px;
  padding: 7px 8px 7px 20px;
  box-shadow: 0 6px 30px rgba(0, 0, 0, .5), 0 0 18px rgba(143, 184, 232, .18);
  max-width: 94vw;
}

.yk-tag { font-size: .78rem; color: var(--yk-tx2); white-space: nowrap; }
.yk-tag span { color: var(--yk-shadow); }

.yk-blink { animation: yk-pulse 1.6s ease-in-out infinite; color: var(--yk-paper); }
@keyframes yk-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .45; }
}

.yk-enter { border-radius: 30px; }

/* ---------------- 响应式 ---------------- */

@media (max-width: 1024px) {
  .yk-mason { columns: 2; }
  .yk-herogrid { grid-template-columns: minmax(0, 6fr) minmax(0, 5fr); }
  .yk-fgrid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .yk-nav, .yk-hact { display: none; }
  .yk-burger { display: block; }

  .yk-navtog:checked ~ .yk-mnav { display: block; }
  .yk-mnav {
    border-top: 1px solid var(--yk-line);
    background: #171c23;
    display: none;
  }
  .yk-mgrp { padding: 12px 22px 4px; }
  .yk-mgrp h3 { font-family: var(--yk-body); font-size: .74rem; letter-spacing: 1.8px; text-transform: uppercase; color: var(--yk-shadow); }
  .yk-mgrp a { display: block; padding: 8px 0; color: var(--yk-tx2); border-bottom: 1px dashed rgba(143, 184, 232, .18); }
  .yk-mgrp a:hover { color: var(--yk-paper); }

  .yk-herogrid { grid-template-columns: 1fr; }
  .yk-cranewrap { height: 230px; max-width: 420px; }
  .yk-fsteps { grid-template-columns: repeat(2, 1fr); }
  .yk-edges { grid-template-columns: 1fr; }
  .yk-fgrid { grid-template-columns: 1fr 1fr; gap: 18px; }
  .yk-paper { padding: 22px 16px 40px; }
}

@media (max-width: 480px) {
  .yk-mason { columns: 1; }
  .yk-fsteps { grid-template-columns: 1fr; }
  .yk-fgrid { grid-template-columns: 1fr; }
  .yk-floatin { gap: 10px; padding-left: 14px; }
  .yk-tag { display: none; }
  .yk-hero { padding-top: 36px; }
}

@media (prefers-reduced-motion: reduce) {
  .yk-blink { animation: none; }
  html { scroll-behavior: auto; }
}