/* 活动中心 v2：首屏直接给出三项奖励，下方每个活动一行讲清「怎么参加」。 */
.av-page{--av-ink:#1f2622;--av-muted:#56615a;--av-green:#16723c;--av-green-deep:#123b24;--av-line:#e3e9e4;--av-soft:#f4f7f4;color:var(--av-ink)}
:where(.av-page) :where(h1,h2,h3,p,ol){margin:0}
:where(.av-page) :where(ol){list-style:none;padding:0}

.av-hero{padding:56px 0 64px;background:linear-gradient(180deg,#f3f8f4 0%,#fff 100%)}
.av-hero-head{text-align:center;max-width:760px;margin:0 auto 40px}
.av-kicker{display:inline-block;font-size:14px;font-weight:600;color:var(--av-green);letter-spacing:.08em;margin-bottom:12px}
.av-hero h1{font-size:48px;line-height:1.25;font-weight:700;letter-spacing:-.01em}
.av-hero-sub{font-size:17px;line-height:1.7;color:var(--av-muted);margin-top:16px}

.av-rewards{display:grid;grid-template-columns:1.25fr 1fr 1fr;gap:20px}
.av-reward{position:relative;display:flex;flex-direction:column;padding:30px 30px 26px;border:1px solid var(--av-line);border-radius:22px;background:#fff;min-height:290px}
.av-reward-name{font-size:17px;font-weight:600}
.av-reward-value{display:flex;align-items:baseline;gap:8px;margin-top:20px;color:var(--av-green);font-variant-numeric:tabular-nums}
.av-reward-value strong{font-size:60px;line-height:1;font-weight:700;letter-spacing:-.02em}
.av-reward-value span{font-size:18px;font-weight:600}
.av-reward-value .av-reward-prefix{align-self:center;font-size:16px}
.av-reward-value .av-reward-text{font-size:34px}
.av-reward-unit{font-size:15px;line-height:1.6;color:var(--av-muted);margin-top:14px}
.av-reward-cta{display:inline-flex;align-items:center;gap:6px;margin-top:auto;padding-top:24px;font-size:15px;font-weight:600;color:var(--av-green)}
.av-reward-cta svg{width:18px;height:18px;transition:transform .2s}
.av-reward-cta:hover svg{transform:translateX(3px)}
.av-reward-invite{background:var(--av-green-deep);border-color:var(--av-green-deep);color:#fff}
.av-reward-invite .av-reward-value{color:#fff}
.av-reward-invite .av-reward-value strong{font-size:76px}
.av-reward-invite .av-reward-unit{color:#c3dacb}
.av-reward-invite .av-reward-cta{color:#9fe0b5}
.av-reward-sprites{position:absolute;top:22px;right:20px;display:flex}
.av-reward-sprites .av-sprite{width:58px;margin-left:-14px}

.av-sprite{display:block;aspect-ratio:1;background-repeat:no-repeat;background-size:300% 400%;background-position:0 0;mix-blend-mode:multiply}

.av-how{padding:56px 0 40px}
.av-section-title{font-size:34px;line-height:1.3;font-weight:700;text-align:center;margin-bottom:36px}
.av-row{display:grid;grid-template-columns:minmax(0,380px) minmax(0,1fr);gap:56px;align-items:center;padding:44px 0;border-top:1px solid var(--av-line);scroll-margin-top:90px}
.av-row:last-child{border-bottom:1px solid var(--av-line)}
.av-row-tag{font-size:14px;font-weight:600;color:var(--av-green);margin-bottom:10px}
.av-row-copy h3{font-size:27px;line-height:1.4;font-weight:700}
.av-row-copy>p:not(.av-row-tag){font-size:16px;line-height:1.75;color:var(--av-muted);margin-top:12px}
.av-row-actions{display:flex;flex-wrap:wrap;align-items:center;gap:12px 16px;margin-top:24px}
.av-row-actions>span{font-size:14px;color:var(--av-muted)}
.av-page .btn{min-height:48px;font-size:15px}

/* 邀请：每步奖励叠加成阶梯，一眼看出越往后拿得越多。 */
.av-stairs{--av-bar-max:210px;display:grid;grid-template-columns:repeat(var(--av-steps,4),minmax(0,1fr));gap:14px;align-items:end}
.av-stairs li{display:flex;flex-direction:column;text-align:center}
.av-stair-gain{font-size:22px;font-weight:700;color:var(--av-green);font-variant-numeric:tabular-nums;margin-bottom:8px}
.av-stair-bar{display:flex;align-items:flex-start;justify-content:center;height:calc(var(--av-bar-max) * var(--av-ratio) / 100);min-height:44px;padding-top:12px;border-radius:12px 12px 4px 4px;background:linear-gradient(180deg,#2f8f55,#16723c);color:#fff;font-size:13px;font-weight:500;transform-origin:bottom;transition:transform .8s cubic-bezier(.16,1,.3,1)}
.av-stairs li:nth-child(1) .av-stair-bar{background:#cfe6d7;color:var(--av-green-deep)}
.av-stairs li:nth-child(2) .av-stair-bar{background:#8cc5a0;color:var(--av-green-deep)}
.av-stairs li:nth-child(3) .av-stair-bar{background:#3d9a62}
.av-stair-label{display:flex;flex-direction:column;align-items:center;justify-content:flex-start;gap:6px;min-height:62px;margin-top:12px;font-size:15px;font-weight:600;line-height:1.4}
.av-stair-label svg{width:22px;height:22px;color:var(--av-green)}
.av-stairs.av-animate .av-stair-bar{transform:scaleY(.08)}
.av-stairs.av-animate.is-in .av-stair-bar{transform:none}
.av-stairs.av-animate.is-in li:nth-child(2) .av-stair-bar{transition-delay:.12s}
.av-stairs.av-animate.is-in li:nth-child(3) .av-stair-bar{transition-delay:.24s}
.av-stairs.av-animate.is-in li:nth-child(4) .av-stair-bar{transition-delay:.36s}

/* 学生认证：三步横排。 */
.av-steps{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;position:relative}
.av-steps:before{content:"";position:absolute;top:32px;left:16.66%;right:16.66%;height:2px;background:var(--av-line)}
.av-steps li{position:relative;display:flex;flex-direction:column;align-items:center;text-align:center;gap:4px}
.av-step-icon{display:grid;place-items:center;width:64px;height:64px;border-radius:50%;background:#fff;border:2px solid var(--av-line);color:var(--av-green);margin-bottom:12px}
.av-step-icon svg{width:26px;height:26px}
.av-steps strong{font-size:18px;font-weight:700}
.av-steps small{font-size:14px;color:var(--av-muted)}
.av-steps .is-reward .av-step-icon{background:var(--av-green);border-color:var(--av-green);color:#fff}
.av-steps .is-reward strong{font-size:24px;color:var(--av-green)}

/* 成长计划：三个里程碑形象。 */
.av-milestones{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.av-milestones li{display:flex;flex-direction:column;align-items:center;text-align:center;padding:18px 12px 22px;border-radius:18px;background:var(--av-soft)}
.av-milestones .av-sprite{width:min(100%,150px)}
.av-milestones strong{font-size:40px;line-height:1.1;font-weight:700;color:var(--av-green);margin-top:6px}
.av-milestones strong small{font-size:16px;margin-left:3px}
.av-milestone-name{font-size:16px;font-weight:600;margin-top:6px}
.av-milestone-gain{display:flex;flex-wrap:wrap;justify-content:center;gap:0 6px;font-size:13px;color:var(--av-muted);margin-top:4px}
.av-milestone-gain>span+span:before{content:"·";margin-right:6px}

/* 规则区：放大旧样式里偏小的字号，免责说明只在这里出现一次。 */
.av-page .faq-section{padding:72px 0 80px}
.av-page .faq-section .section-head h2{font-size:30px}
.av-page .faq-section .section-head p{font-size:15px}
.av-page .faq-q{font-size:16px}
.av-page .faq-a-inner{font-size:15px;line-height:1.85}

@media(max-width:1060px){
  .av-rewards{grid-template-columns:1fr 1fr}
  .av-reward-invite{grid-column:1/-1;min-height:0}
  .av-row{grid-template-columns:1fr;gap:32px}
  .av-stairs{--av-bar-max:190px}
}
@media(max-width:640px){
  .av-hero{padding:36px 0 44px}
  .av-hero-head{margin-bottom:28px}
  .av-hero h1{font-size:34px}
  .av-hero-sub{font-size:15px}
  .av-rewards{grid-template-columns:1fr;gap:14px}
  .av-reward{padding:24px 22px 20px;min-height:0}
  .av-reward-value strong{font-size:50px}
  .av-reward-invite .av-reward-value strong{font-size:60px}
  .av-reward-cta{padding-top:18px}
  .av-reward-sprites{top:16px;right:14px}
  .av-reward-sprites .av-sprite{width:48px}
  .av-how{padding:48px 0 24px}
  .av-section-title{font-size:28px;margin-bottom:20px}
  .av-row{padding:32px 0;gap:26px}
  .av-row-copy h3{font-size:23px}
  .av-row-copy>p:not(.av-row-tag){font-size:15px}
  .av-stairs{--av-bar-max:160px;gap:8px}
  .av-stair-gain{font-size:17px}
  .av-stair-bar{font-size:11px;padding-top:8px}
  .av-stair-label{font-size:12px;gap:4px}
  .av-stair-label svg{width:18px;height:18px}
  .av-steps strong{font-size:15px}
  .av-steps small{font-size:13px}
  .av-steps .is-reward strong{font-size:18px}
  .av-step-icon{width:54px;height:54px}
  .av-steps:before{top:27px}
  .av-milestones{gap:8px}
  .av-milestones li{padding:12px 6px 16px}
  .av-milestones strong{font-size:30px}
  .av-milestone-name{font-size:14px}
  .av-milestone-gain{flex-direction:column;font-size:12px;line-height:1.6}
  .av-milestone-gain>span+span:before{content:none}
  .av-page .faq-section{padding:48px 0 96px}
  .av-page .faq-section .section-head h2{font-size:25px}
  .av-page .faq-q{font-size:15px}
  .av-page .faq-a-inner{font-size:14px}
}
@media(prefers-reduced-motion:reduce){
  .av-stairs.av-animate .av-stair-bar{transform:none;transition:none}
}