/* ==========================================================================
   ACM 实验室招新 · acm-lab
   视觉方向：赛场气球（ICPC 解出题目得气球 × 判定/记分牌元素）
   ========================================================================== */

/* 得意黑 Smiley Sans · SIL Open Font License 1.1 */
@font-face {
  font-family: "Smiley Sans";
  src: url("../assets/fonts/smiley-sans.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

:root {
  --paper: #f7f9fc;
  --paper-tint: #edf2fb;
  --ink: #1b1d2a;
  --muted: #5a6072;
  --line: #e3e7f0;

  /* 气球色组 */
  --c-red: #ff5a5f;
  --c-yellow: #ffc53d;
  --c-blue: #4d96ff;
  --c-green: #3ecf8e;
  --c-purple: #9b5de5;

  --ac-green: #00a854;
  --ac-green-dark: #008f47;
  --link: #2a66d9;

  --font-display: "Smiley Sans", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", sans-serif;
  --font-body: system-ui, -apple-system, "PingFang SC", "HarmonyOS Sans SC",
    "Source Han Sans SC", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;

  --hard-sm: 3px 3px 0 var(--ink);
  --hard-md: 5px 5px 0 var(--ink);
  --hard-lg: 7px 7px 0 var(--ink);

  --wrap: 1080px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.75;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(180deg, #e8f1ff 0%, rgba(247, 249, 252, 0) 340px),
    linear-gradient(0deg, #efeafb 0%, rgba(247, 249, 252, 0) 460px);
  background-repeat: no-repeat;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
}

a {
  color: var(--link);
  text-decoration-color: rgba(42, 102, 217, 0.35);
  text-underline-offset: 3px;
}
a:hover {
  text-decoration-color: currentColor;
}

:focus-visible {
  outline: 3px solid rgba(77, 150, 255, 0.5);
  outline-offset: 2px;
  border-radius: 6px;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-display);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: 0.01em;
}

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 clamp(18px, 4vw, 32px);
}

section[id] {
  scroll-margin-top: 76px;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  z-index: 100;
  background: #fff;
  color: var(--ink);
  padding: 10px 18px;
  border-radius: 0 0 10px 0;
}
.skip-link:focus {
  left: 0;
}

/* --------------------------------------------------------------------------
   顶部导航
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.97), rgba(246, 249, 255, 0.93));
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 2px solid var(--ink);
}
.site-header::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 4px;
  pointer-events: none;
  background: linear-gradient(
    90deg,
    var(--c-red) 0 20%,
    var(--c-yellow) 20% 40%,
    var(--c-green) 40% 60%,
    var(--c-blue) 60% 80%,
    var(--c-purple) 80% 100%
  );
}

.header-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 5px 12px;
  font-family: var(--font-display);
  font-size: 20px;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
  background: #fff;
  border: 2px solid var(--ink);
  border-radius: 10px;
  box-shadow: 2px 2px 0 var(--ink);
  transform: rotate(-1.5deg);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}
.brand:hover {
  transform: rotate(-1.5deg) translate(-1px, -1px);
  box-shadow: 3px 3px 0 var(--ink);
}
.brand::after {
  content: "";
  width: 30px;
  height: 7px;
  border-radius: 999px;
  border: 1.5px solid var(--ink);
  background: linear-gradient(
    90deg,
    var(--c-red) 0 20%,
    var(--c-yellow) 20% 40%,
    var(--c-green) 40% 60%,
    var(--c-blue) 60% 80%,
    var(--c-purple) 80% 100%
  );
}

.brand-balloon {
  position: relative;
  width: 15px;
  height: 19px;
  flex: none;
  background: var(--c-red);
  border: 2px solid var(--ink);
  border-radius: 50% 50% 50% 50% / 45% 45% 52% 52%;
}
.brand-balloon::after {
  content: "";
  position: absolute;
  left: 50%;
  top: calc(100% + 1px);
  width: 5px;
  height: 5px;
  background: var(--c-red);
  transform: translateX(-50%) rotate(45deg);
}

.site-menu {
  display: flex;
  align-items: center;
  gap: clamp(4px, 1.2vw, 10px);
}

.site-menu a {
  position: relative;
  color: var(--muted);
  text-decoration: none;
  font-size: 15.5px;
  padding: 6px 12px;
  border: 2px solid transparent;
  border-radius: 9px;
  transition: color 0.18s ease, background 0.18s ease, border-color 0.18s ease,
    box-shadow 0.18s ease, transform 0.18s ease;
}
.site-menu a:hover {
  color: var(--ink);
  background: rgba(27, 29, 42, 0.06);
}
.site-menu a.is-active {
  color: var(--ink);
  font-weight: 600;
  background: var(--nav-bg, #e8f0ff);
  border-color: var(--ink);
  box-shadow: 2px 2px 0 var(--ink);
  transform: rotate(-1.5deg);
}
.site-menu a[data-nav="gains"] {
  --nav-accent: var(--c-yellow);
  --nav-bg: #fff3c9;
}
.site-menu a[data-nav="about"] {
  --nav-accent: var(--c-purple);
  --nav-bg: #f0e4ff;
}
.site-menu a[data-nav="selection"] {
  --nav-accent: var(--c-blue);
  --nav-bg: #e2eeff;
}
.site-menu a[data-nav="qa"] {
  --nav-accent: var(--c-green);
  --nav-bg: #ddf7e8;
}
.site-menu .menu-cta.is-active {
  box-shadow: 0 0 0 3px rgba(0, 168, 84, 0.28), var(--hard-sm);
}

/* 顶栏迷你气球 */
.header-balloons {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.hb {
  position: absolute;
  height: auto;
  animation: balloon-float 6s ease-in-out infinite;
}
.hb-1 {
  width: 27px;
  left: 33%;
  top: 4px;
}
.hb-2 {
  width: 21px;
  left: 37%;
  top: 22px;
  animation-delay: -2s;
}
.hb-3 {
  width: 17px;
  left: 30.5%;
  top: 30px;
  animation-delay: -4s;
}
@media (max-width: 1080px) {
  .header-balloons {
    display: none;
  }
}

.site-menu .menu-cta {
  color: #fff;
  background: var(--ac-green);
  padding: 8px 18px;
  border: 2px solid var(--ink);
  border-radius: 10px;
  font-weight: 600;
  box-shadow: var(--hard-sm);
  transition: transform 0.16s ease, box-shadow 0.16s ease, background 0.18s ease;
}
.site-menu .menu-cta:hover {
  background: var(--ac-green-dark);
  color: #fff;
  transform: translate(-2px, -2px);
  box-shadow: var(--hard-md);
}
.site-menu .menu-cta:active {
  transform: translate(1px, 1px);
  box-shadow: 2px 2px 0 var(--ink);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 0 10px;
  background: none;
  border: 0;
  cursor: pointer;
}
.nav-toggle-bar {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   Hero
   -------------------------------------------------------------------------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: clamp(64px, 12vh, 128px) 0 clamp(56px, 9vh, 96px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(620px 460px at 76% 18%, rgba(255, 255, 255, 0.9), transparent 62%),
    radial-gradient(640px 420px at 78% 30%, rgba(77, 150, 255, 0.16), transparent 70%),
    radial-gradient(520px 360px at 16% 82%, rgba(255, 197, 61, 0.16), transparent 70%),
    linear-gradient(
      180deg,
      #d3e5ff 0%,
      #e7f1ff 50%,
      rgba(247, 249, 252, 0.55) 86%,
      rgba(247, 249, 252, 0) 100%
    );
}

.hero-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  align-items: center;
  gap: clamp(24px, 4vw, 56px);
}

.hero-status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 6px 14px;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  background: #fff;
  border: 2px solid var(--ink);
  border-radius: 999px;
  box-shadow: var(--hard-sm);
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ac-green);
  animation: dot-pulse 2s ease-in-out infinite;
}

@keyframes dot-pulse {
  50% {
    opacity: 0.35;
    scale: 0.8;
  }
}

.hero-title {
  margin: 20px 0 18px;
  font-size: clamp(40px, 6.2vw, 74px);
  line-height: 1.14;
}

.hero-title .hl {
  display: inline-block;
  padding: 0 0.14em;
  margin: 2px -2px 0 2px;
  background: #ffd94d;
  border: 3px solid var(--ink);
  border-radius: 10px;
  box-shadow: 6px 6px 0 var(--ink);
  transform: rotate(-1.2deg);
}

.hero-sub {
  margin: 0 0 34px;
  max-width: 34em;
  font-size: clamp(16px, 1.35vw, 18px);
  color: var(--muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 10px;
  border: 2px solid var(--ink);
  font-family: inherit;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.4;
  text-decoration: none;
  cursor: pointer;
  box-shadow: var(--hard-sm);
  transition: transform 0.16s ease, box-shadow 0.16s ease, background 0.18s ease,
    border-color 0.18s ease, color 0.18s ease;
}
.btn:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--hard-md);
}
.btn:active {
  transform: translate(1px, 1px);
  box-shadow: 2px 2px 0 var(--ink);
}
.btn-primary {
  position: relative;
  overflow: hidden;
  background: var(--ac-green);
  color: #fff;
}
.btn-primary:hover {
  background: var(--ac-green-dark);
}
.btn-primary::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: -70%;
  width: 40%;
  background: linear-gradient(105deg, transparent, rgba(255, 255, 255, 0.5), transparent);
  transform: translateX(0) skewX(-18deg);
  animation: btn-sheen 4.2s ease-in-out infinite;
  animation-delay: 1.4s;
  pointer-events: none;
}

@keyframes btn-sheen {
  0%,
  58% {
    transform: translateX(0) skewX(-18deg);
  }
  88%,
  100% {
    transform: translateX(430%) skewX(-18deg);
  }
}
.btn-ghost {
  background: #fff;
  color: var(--ink);
  border-color: var(--ink);
}
.btn-ghost:hover {
  background: #fff;
}

/* Hero 入场编排（一次性） */
.js .hero-copy > * {
  animation: rise 0.7s cubic-bezier(0.2, 0.7, 0.2, 1) both;
}
.js .hero-copy > *:nth-child(1) { animation-delay: 0.05s; }
.js .hero-copy > *:nth-child(2) { animation-delay: 0.14s; }
.js .hero-copy > *:nth-child(3) { animation-delay: 0.23s; }
.js .hero-copy > *:nth-child(4) { animation-delay: 0.32s; }

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* 气球 */
.balloons {
  position: relative;
  min-height: clamp(380px, 42vw, 520px);
}

.balloon {
  position: absolute;
  height: auto;
  cursor: pointer;
  scale: 1;
  transform-origin: 50% 85%;
  transition: scale 0.25s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.25s ease;
  animation: balloon-float 7s ease-in-out infinite;
}

.js .balloon {
  animation-name: balloon-enter, balloon-float;
  animation-duration: 0.7s, 7s;
  animation-timing-function: cubic-bezier(0.2, 0.7, 0.3, 1.35), ease-in-out;
  animation-iteration-count: 1, infinite;
  animation-fill-mode: backwards, none;
}

.balloon:hover {
  scale: 1.07;
}

.balloon.popped {
  scale: 0.1;
  opacity: 0;
}

.b-red {
  width: 30%;
  left: 4%;
  top: 14%;
  color: var(--c-red);
  animation-delay: 0.55s, -0.5s;
}
.b-blue {
  width: 27%;
  right: 4%;
  top: 0;
  color: var(--c-blue);
  animation-delay: 0.75s, -2.5s;
}
.b-yellow {
  width: 21%;
  left: 36%;
  top: 2%;
  color: var(--c-yellow);
  animation-delay: 0.4s, -4s;
}
.b-green {
  width: 19%;
  left: 14%;
  top: 52%;
  color: var(--c-green);
  animation-delay: 0.95s, -1.5s;
}
.b-purple {
  width: 17%;
  right: 24%;
  top: 44%;
  color: var(--c-purple);
  animation-delay: 1.1s, -3s;
}

@keyframes balloon-enter {
  from {
    opacity: 0;
    scale: 0.3;
  }
  to {
    opacity: 1;
    scale: 1;
  }
}

@keyframes balloon-float {
  50% {
    transform: translateY(-12px);
  }
}

/* 升空气球流 */
.balloon-stream {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.rise {
  position: absolute;
  bottom: -300px;
  width: var(--w, 40px);
  height: calc(var(--w, 40px) * 1.25);
  background: var(--bc, var(--c-red));
  border: 2px solid var(--ink);
  border-radius: 50% 50% 50% 50% / 45% 45% 54% 54%;
  opacity: var(--o, 0.5);
  animation: balloon-rise var(--dur, 18s) linear infinite;
  animation-delay: var(--delay, 0s);
}
.rise::before {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  width: 2px;
  height: 64px;
  background: linear-gradient(180deg, rgba(27, 29, 42, 0.2), rgba(27, 29, 42, 0));
  transform: translateX(-50%);
}
.rise::after {
  content: "";
  position: absolute;
  top: calc(100% - 3px);
  left: 50%;
  width: 8px;
  height: 8px;
  background: var(--bc, var(--c-red));
  border: 2px solid var(--ink);
  border-radius: 2px;
  transform: translateX(-50%) rotate(45deg);
}

.r1 { left: 4%;  --w: 38px; --bc: var(--c-blue);   --dur: 19s; --delay: -2s;  --o: 0.5; }
.r2 { left: 13%; --w: 24px; --bc: var(--c-yellow); --dur: 15s; --delay: -9s;  --o: 0.55; }
.r3 { left: 23%; --w: 32px; --bc: var(--c-red);    --dur: 22s; --delay: -14s; --o: 0.45; }
.r4 { left: 34%; --w: 20px; --bc: var(--c-green);  --dur: 16s; --delay: -5s;  --o: 0.55; }
.r5 { left: 46%; --w: 44px; --bc: var(--c-purple); --dur: 24s; --delay: -18s; --o: 0.45; }
.r6 { left: 58%; --w: 26px; --bc: var(--c-blue);   --dur: 17s; --delay: -1s;  --o: 0.65; }
.r7 { left: 68%; --w: 36px; --bc: var(--c-yellow); --dur: 21s; --delay: -11s; --o: 0.6; }
.r8 { left: 80%; --w: 22px; --bc: var(--c-red);    --dur: 14s; --delay: -7s;  --o: 0.7; }
.r9 { left: 91%; --w: 30px; --bc: var(--c-green);  --dur: 20s; --delay: -3s;  --o: 0.6; }

@keyframes balloon-rise {
  0% {
    transform: translate3d(0, 0, 0) rotate(-3deg);
  }
  50% {
    transform: translate3d(18px, -48vh, 0) rotate(4deg);
  }
  100% {
    transform: translate3d(-10px, calc(-100vh - 340px), 0) rotate(-3deg);
  }
}

/* 戳破彩蛋 */
.pop-plus {
  position: absolute;
  z-index: 3;
  font-family: var(--font-display);
  font-size: 16px;
  color: var(--ac-green);
  background: #fff;
  border: 2px solid var(--ink);
  border-radius: 8px;
  padding: 1px 10px;
  box-shadow: 2px 2px 0 var(--ink);
  pointer-events: none;
  animation: plus-float 0.9s ease-out forwards;
}

@keyframes plus-float {
  from {
    opacity: 1;
    transform: translate(-50%, -50%);
  }
  to {
    opacity: 0;
    transform: translate(-50%, -190%);
  }
}

/* --------------------------------------------------------------------------
   通用 Section
   -------------------------------------------------------------------------- */
.section {
  position: relative;
  overflow: hidden;
  padding: clamp(64px, 9vw, 112px) 0;
}
.section::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background: var(--wash, none);
}
.section-tint {
  background-color: rgba(237, 242, 252, 0.72);
  background-image: radial-gradient(rgba(27, 29, 42, 0.05) 1px, transparent 1.2px);
  background-size: 22px 22px;
}

#gains {
  --head-accent: var(--c-yellow);
  --wash:
    radial-gradient(760px 480px at 92% 6%, rgba(255, 197, 61, 0.08), transparent 72%),
    radial-gradient(640px 460px at 0% 82%, rgba(62, 207, 142, 0.07), transparent 70%);
}
#about {
  --head-accent: var(--c-purple);
  --wash:
    radial-gradient(680px 420px at 8% 10%, rgba(155, 93, 229, 0.08), transparent 70%),
    radial-gradient(560px 420px at 96% 86%, rgba(77, 150, 255, 0.07), transparent 72%);
}
#selection {
  --head-accent: var(--c-blue);
  --wash:
    radial-gradient(720px 480px at 96% 24%, rgba(77, 150, 255, 0.08), transparent 70%),
    radial-gradient(560px 400px at 2% 92%, rgba(255, 90, 95, 0.06), transparent 72%);
}
#qa {
  --head-accent: var(--c-green);
  --wash:
    radial-gradient(680px 420px at 4% 30%, rgba(255, 197, 61, 0.07), transparent 70%),
    radial-gradient(600px 420px at 94% 78%, rgba(77, 150, 255, 0.06), transparent 72%);
}
#join {
  --head-accent: var(--c-red);
  --wash:
    radial-gradient(700px 460px at 10% 20%, rgba(62, 207, 142, 0.08), transparent 70%),
    radial-gradient(620px 440px at 92% 82%, rgba(155, 93, 229, 0.08), transparent 72%);
}

.wrap {
  position: relative;
  z-index: 1;
}

.section-head {
  max-width: 46em;
}
.section-head h2 {
  margin: 0 0 10px;
  font-size: clamp(28px, 3.8vw, 44px);
}
.section-head h2::after,
.join-copy h2::after {
  content: "";
  display: block;
  width: 68px;
  height: 8px;
  margin-top: 14px;
  border: 2px solid var(--ink);
  border-radius: 4px;
  background: var(--head-accent, var(--c-blue));
}
.section-sub {
  margin: 0;
  color: var(--muted);
}

/* 滚动显现（JS 控制，禁用时保持可见） */
.js .reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.js .reveal.in {
  opacity: 1;
  transform: none;
}

/* --------------------------------------------------------------------------
   收获区块
   -------------------------------------------------------------------------- */
.gain {
  margin-top: clamp(40px, 6vw, 72px);
  padding-top: clamp(28px, 4vw, 44px);
  border-top: 1px solid var(--line);
}

.gain-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}
.gain-head h3 {
  margin: 0;
  font-size: clamp(20px, 2.3vw, 27px);
}

.gain-dot {
  position: relative;
  flex: none;
  width: 14px;
  height: 18px;
  background: var(--accent, var(--c-red));
  border: 2px solid var(--ink);
  border-radius: 50% 50% 50% 50% / 45% 45% 52% 52%;
}
.gain-dot::after {
  content: "";
  position: absolute;
  left: 50%;
  top: calc(100% + 1px);
  width: 5px;
  height: 5px;
  background: var(--accent, var(--c-red));
  transform: translateX(-50%) rotate(45deg);
}

.gain > p {
  max-width: 62em;
}

.gain-note {
  color: var(--muted);
  font-size: 14.5px;
}

/* 两栏（文字 + 图） */
.gain.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}
.gain.flip .gain-figs {
  order: -1;
}
.gain-body > p:first-child {
  margin-top: 0;
}

.gain-figs {
  display: grid;
  gap: 14px;
  margin: 0;
}
.gain-figs img {
  display: block;
  width: 100%;
  height: auto;
  border: 2px solid var(--ink);
  border-radius: 10px;
  background: #fff;
  box-shadow: 3px 3px 0 var(--ink);
}
.gain-figs.narrow {
  justify-items: center;
}
.gain-figs.narrow img {
  width: min(100%, 400px);
}

/* 列表 */
.plain-list {
  margin: 0;
  padding-left: 1.25em;
}
.plain-list li + li {
  margin-top: 8px;
}
.plain-list li::marker {
  color: #b9c0d0;
}

/* 荣誉清单 */
.honors {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px clamp(24px, 4vw, 56px);
  margin: 22px 0 30px;
}

.honor-year h4 {
  margin: 0 0 6px;
  font-size: 21px;
  color: var(--ink);
}
.honor-year:nth-child(4n + 1) h4 { color: #c23b40; }
.honor-year:nth-child(4n + 2) h4 { color: #b07f00; }
.honor-year:nth-child(4n + 3) h4 { color: #2f6fd0; }
.honor-year:nth-child(4n) h4 { color: #1f9d5b; }

.honor-list {
  margin: 0;
  padding: 0;
  list-style: none;
}
.honor-list li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 7px 0;
  border-bottom: 1px solid var(--line);
  font-size: 15px;
}

.medal {
  flex: none;
  padding: 1px 9px;
  border-radius: 6px;
  border: 1.5px solid var(--ink);
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
}
.m-gold {
  background: #fff3d1;
  color: #96690a;
}
.m-silver {
  background: #edf1f7;
  color: #58627a;
}
.m-bronze {
  background: #fbeadd;
  color: #8f4f26;
}
.m-hon {
  background: #eef4ee;
  color: #4c7a5c;
}

/* 奖励政策 */
.rewards {
  display: flex;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
  max-width: 620px;
  border: 2px solid var(--ink);
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
  box-shadow: var(--hard-md);
}
.rewards li {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 16px 12px;
  font-size: 15.5px;
  white-space: nowrap;
}
.rewards li + li {
  border-left: 2px solid var(--ink);
}
.rewards strong {
  font-family: var(--font-display);
  font-size: 19px;
  letter-spacing: 0.02em;
}
.reward-dot {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  flex: none;
}
.reward-dot.gold {
  background: #e8b004;
}
.reward-dot.silver {
  background: #a9b2c3;
}
.reward-dot.bronze {
  background: #c1743f;
}

/* --------------------------------------------------------------------------
   图集
   -------------------------------------------------------------------------- */
.gallery {
  display: grid;
  gap: clamp(12px, 2vw, 18px);
  margin: 22px 0 0;
}
.gallery-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: start;
}
.gallery-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}
.gallery-stack {
  grid-template-columns: 1fr;
  max-width: 860px;
}

.g-item {
  margin: 0;
  transition: transform 0.18s ease;
}
.g-item:hover {
  transform: translate(-2px, -2px);
}
.g-item img {
  display: block;
  width: 100%;
  height: auto;
  border: 2px solid var(--ink);
  border-radius: 10px;
  background: #fff;
  box-shadow: 3px 3px 0 var(--ink);
}
.g-item figcaption {
  padding-top: 7px;
  font-size: 13.5px;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   比赛介绍
   -------------------------------------------------------------------------- */
.about-body {
  max-width: 62em;
}
.about-body p {
  margin: 0 0 14px;
}

.link-cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  max-width: 720px;
  margin-top: 26px;
}

.link-card {
  display: block;
  padding: 20px 22px;
  border: 2px solid var(--ink);
  border-radius: 12px;
  background: #fff;
  color: var(--ink);
  text-decoration: none;
  box-shadow: var(--hard-sm);
  transition: border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}
.link-card:hover {
  border-color: var(--ink);
  transform: translate(-3px, -3px);
  box-shadow: var(--hard-md);
  text-decoration: none;
}
.link-card-title {
  display: block;
  font-family: var(--font-display);
  font-size: 18.5px;
  margin-bottom: 4px;
}
.link-card-url {
  font-size: 13.5px;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   选拔流程（时间线）
   -------------------------------------------------------------------------- */
.steps {
  margin: 36px 0 0;
  padding: 0;
  list-style: none;
}

.step {
  position: relative;
  padding: 0 0 clamp(44px, 7vw, 72px) clamp(52px, 6vw, 78px);
}
.step:last-child {
  padding-bottom: 0;
}
.step::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 46px;
  bottom: 4px;
  width: 3px;
  background: rgba(27, 29, 42, 0.14);
}
.step:last-child::before {
  display: none;
}

.step-marker {
  position: absolute;
  left: 0;
  top: 0;
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--accent, var(--c-blue));
  border: 2px solid var(--ink);
  box-shadow: var(--hard-sm);
  color: #fff;
  font-family: var(--font-display);
  font-size: 21px;
  line-height: 1;
}

.step-body h3 {
  margin: 3px 0 12px;
  font-size: clamp(20px, 2.4vw, 27px);
}
.step-body > p:first-child {
  margin-top: 0;
}

.substeps {
  margin: 10px 0 16px;
  padding-left: 1.3em;
}
.substeps li + li {
  margin-top: 6px;
}
.substeps li::marker {
  color: var(--accent, var(--c-blue));
  font-family: var(--font-display);
}

.step .gallery {
  margin-top: 18px;
}

/* --------------------------------------------------------------------------
   Q&A
   -------------------------------------------------------------------------- */
.faq {
  margin-top: 30px;
  border: 2px solid var(--ink);
  border-radius: 14px;
  background: #fff;
  box-shadow: var(--hard-md);
  overflow: hidden;
}
.faq details {
  border-bottom: 2px solid var(--ink);
}
.faq details:last-child {
  border-bottom: 0;
}
.faq summary {
  position: relative;
  padding: 19px 56px 19px 20px;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}
.faq summary::-webkit-details-marker {
  display: none;
}
.faq summary::after {
  content: "+";
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-display);
  font-size: 24px;
  color: var(--muted);
  transition: transform 0.2s ease;
}
.faq details[open] summary::after {
  transform: translateY(-50%) rotate(45deg);
}
.faq details p {
  margin: 0 0 20px;
  padding: 0 20px;
  max-width: 72ch;
  color: var(--muted);
}

.doc-link {
  margin: 30px 0 0;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   加入我们
   -------------------------------------------------------------------------- */
.join-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 340px);
  gap: clamp(32px, 5vw, 72px);
  align-items: center;
}
.join-copy h2 {
  margin: 0 0 12px;
  font-size: clamp(28px, 3.8vw, 44px);
}
.join-copy > p {
  margin: 0;
  max-width: 36em;
  color: var(--muted);
}

.group-number {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px 18px;
  margin-top: 26px;
}
.gnum-label {
  font-size: 14px;
  color: var(--muted);
}
.gnum {
  font-family: var(--font-display);
  font-size: clamp(26px, 3vw, 34px);
  letter-spacing: 0.03em;
}

.join-qr {
  margin: 0;
}
.qr-card {
  display: inline-block;
  max-width: 100%;
  padding: 18px 18px 14px;
  background: #fff;
  border: 2px solid var(--ink);
  border-radius: 18px;
  box-shadow: var(--hard-lg);
  transform: rotate(-1.2deg);
  text-align: center;
}
.qr-card img {
  display: block;
  width: min(100%, 300px);
  height: auto;
  margin: 0 auto;
  border-radius: 10px;
}
.qr-card p {
  margin: 10px 0 0;
  font-size: 13.5px;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   页脚
   -------------------------------------------------------------------------- */
.site-footer {
  background: var(--ink);
  color: #c9cedd;
  padding: 46px 0 54px;
}
.footer-wrap p {
  margin: 6px 0;
  font-size: 14.5px;
}
.footer-brand {
  font-family: var(--font-display);
  font-size: 20px;
  color: #fff;
}
.site-footer a {
  color: #fff;
  text-decoration-color: rgba(255, 255, 255, 0.4);
}

/* --------------------------------------------------------------------------
   动态元素：进度条 / 五色分隔条 / 荣誉滚动条 / 数据条 / 背景气球
   -------------------------------------------------------------------------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 80;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(
    90deg,
    var(--c-red),
    var(--c-yellow) 25%,
    var(--c-green) 50%,
    var(--c-blue) 75%,
    var(--c-purple)
  );
  pointer-events: none;
}

.stripe {
  height: 6px;
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
  background: linear-gradient(
    90deg,
    var(--c-red) 0 20%,
    var(--c-yellow) 20% 40%,
    var(--c-green) 40% 60%,
    var(--c-blue) 60% 80%,
    var(--c-purple) 80% 100%
  );
}

.ticker {
  overflow: hidden;
  background: var(--ink);
}
.ticker-track {
  display: flex;
  width: max-content;
}
.ticker-track.running {
  animation: ticker-scroll 46s linear infinite;
}
.ticker:hover .ticker-track.running {
  animation-play-state: paused;
}
.ticker-group {
  display: flex;
  align-items: center;
  gap: 36px;
  padding: 13px 36px 13px 0;
}
.ticker-group span {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  white-space: nowrap;
  font-size: 14.5px;
  color: #c9cedd;
}
.ticker-group b {
  font-weight: 600;
}
.t-dot {
  flex: none;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--c, #a9b2c3);
  box-shadow: 1.5px 1.5px 0 rgba(255, 255, 255, 0.35);
}
.t-gold { color: #96690a; }
.t-silver { color: #58627a; }
.t-bronze { color: #8f4f26; }
.t-hon { color: #4c7a5c; }
.ticker .t-gold { color: #ffd75e; }
.ticker .t-silver { color: #cdd6e6; }
.ticker .t-bronze { color: #eda878; }
.ticker .t-hon { color: #9ee6bc; }

@keyframes ticker-scroll {
  to {
    transform: translateX(-50%);
  }
}

.stats {
  display: flex;
  margin: 18px 0 26px;
  max-width: 620px;
  border: 2px solid var(--ink);
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
  box-shadow: var(--hard-md);
}
.stat {
  flex: 1;
  padding: 12px 6px 10px;
  text-align: center;
}
.stat + .stat {
  border-left: 2px solid var(--ink);
}
.stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(27px, 2.7vw, 34px);
  line-height: 1.25;
}
.stat-label {
  display: block;
  font-size: 13px;
  color: var(--muted);
}

.deco {
  position: absolute;
  height: auto;
  pointer-events: none;
  z-index: 0;
  animation: balloon-float 12s ease-in-out infinite;
}
.deco-1 {
  width: 190px;
  left: -90px;
  top: 56px;
  color: var(--c-red);
  opacity: 0.1;
}
.deco-2 {
  width: 150px;
  right: -30px;
  top: 46%;
  color: var(--c-blue);
  opacity: 0.1;
  animation-delay: -5s;
}
.deco-3 {
  width: 140px;
  right: 4%;
  top: 40px;
  color: var(--c-purple);
  opacity: 0.12;
  animation-delay: -2s;
}
.deco-4 {
  width: 170px;
  left: -70px;
  bottom: 30px;
  color: var(--c-yellow);
  opacity: 0.16;
  animation-delay: -7s;
}

/* --------------------------------------------------------------------------
   响应式
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .gain.split {
    grid-template-columns: 1fr;
  }
  .gain.flip .gain-figs {
    order: 0;
  }
  .gallery-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .join-wrap {
    grid-template-columns: 1fr;
    justify-items: start;
  }
}

@media (max-width: 760px) {
  .deco {
    display: none;
  }
  .nav-toggle {
    display: flex;
  }
  .site-menu {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    padding: 8px 0 14px;
  }
  .site-menu.open {
    display: flex;
  }
  .site-menu a {
    padding: 12px clamp(18px, 4vw, 32px);
    font-size: 16px;
  }
  .site-menu a.is-active {
    background: var(--nav-bg, #e8f0ff);
    border-color: transparent;
    box-shadow: inset 3px 0 0 var(--nav-accent, var(--c-blue));
    transform: none;
  }
  .site-menu .menu-cta.is-active {
    box-shadow: 0 0 0 3px rgba(0, 168, 84, 0.28), var(--hard-sm);
  }
  .site-menu .menu-cta {
    margin: 8px clamp(18px, 4vw, 32px) 0;
    text-align: center;
  }
}

@media (max-width: 860px) {
  .hero-wrap {
    grid-template-columns: 1fr;
  }
  .balloons {
    order: -1;
    min-height: 250px;
  }
  .b-red {
    width: 24%;
    left: 6%;
    top: 4%;
  }
  .b-blue {
    width: 22%;
    right: 6%;
    top: 0;
  }
  .b-yellow {
    width: 18%;
    left: 37%;
    top: 10%;
  }
  .b-green {
    width: 16%;
    left: 17%;
    top: 46%;
  }
  .b-purple {
    width: 14%;
    right: 26%;
    top: 42%;
  }
}

@media (max-width: 640px) {
  .honors {
    grid-template-columns: 1fr;
  }
  .gallery-2,
  .gallery-4,
  .link-cards {
    grid-template-columns: 1fr;
  }
  .join-qr img {
    max-width: 300px;
  }
  .stat-num {
    font-size: 22px;
  }
  .stat-label {
    font-size: 12px;
  }
  .rewards {
    flex-direction: column;
  }
  .rewards li + li {
    border-left: 0;
    border-top: 2px solid var(--ink);
  }
  .rewards li {
    justify-content: flex-start;
  }
}

/* --------------------------------------------------------------------------
   动效降级
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .balloon,
  .js .balloon,
  .js .hero-copy > *,
  .btn-primary::after,
  .status-dot,
  .pop-plus,
  .hb {
    animation: none;
  }
  .balloon-stream {
    display: none;
  }
  .js .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .link-card:hover {
    transform: none;
  }
  .deco,
  .ticker-track.running {
    animation: none;
  }
}