/* ===========================================================
   一滴水的校园账本 — 样式表
   设计基调：水滴蓝 + 校园绿 + 暖白纸感，克制的圆角与阴影
   =========================================================== */

:root{
  --ink:#0f2a33;
  --ink-soft:#2c4a54;
  --muted:#5f7a84;
  --blue:#0d6f8f;
  --blue-deep:#0a4f66;
  --blue-tint:#e6f4f8;
  --green:#2f7a5e;
  --green-tint:#eaf3ec;
  --amber:#a4762a;
  --paper:#f6f5ef;
  --white:#ffffff;
  --line:#e0e9e8;
  --line-strong:#c8d8d7;
  --danger:#a33a2b;
  --radius:18px;
  --radius-sm:12px;
  --shadow-sm:0 1px 2px rgba(15,42,51,.05), 0 8px 24px rgba(15,42,51,.05);
  --shadow-md:0 2px 6px rgba(15,42,51,.06), 0 20px 48px rgba(15,42,51,.09);
  --maxw:1120px;
  --header-h:68px;
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:"PingFang SC","Microsoft YaHei","Noto Sans SC","Hiragino Sans GB",system-ui,sans-serif;
  font-size:16px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
}
img,svg{max-width:100%}
h1,h2,h3,h4{margin:0;line-height:1.25;letter-spacing:-.01em}
p{margin:0 0 .85em}
p:last-child{margin-bottom:0}
a{color:inherit}
ul,ol{margin:0}
:focus-visible{outline:3px solid rgba(13,111,143,.45);outline-offset:2px;border-radius:6px}

.skip-link{position:absolute;left:-9999px}
.skip-link:focus{left:1rem;top:1rem;z-index:100;background:#fff;padding:.7rem 1.1rem;border:2px solid var(--ink);border-radius:10px}

/* ---------- 顶部栏 ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(246,245,239,.86);
  backdrop-filter:saturate(160%) blur(12px);
  -webkit-backdrop-filter:saturate(160%) blur(12px);
  border-bottom:1px solid rgba(200,216,215,.6);
}
.header-inner{
  max-width:var(--maxw);margin:0 auto;padding:0 24px;
  height:var(--header-h);display:flex;align-items:center;gap:28px;
}
.brand{display:inline-flex;align-items:center;gap:.6rem;text-decoration:none;font-weight:800;letter-spacing:-.02em;white-space:nowrap}
.brand-drop{
  width:30px;height:30px;border-radius:50%;
  display:grid;place-items:center;background:var(--blue-tint);
}
.brand-drop svg{width:15px;height:15px;fill:var(--blue)}
.brand-text{font-size:1rem}
.site-nav{display:flex;gap:4px;margin-right:auto}
.site-nav a{
  text-decoration:none;font-size:.9rem;font-weight:600;color:var(--ink-soft);
  padding:.4rem .7rem;border-radius:999px;transition:background .18s,color .18s;
}
.site-nav a:hover{background:rgba(13,111,143,.08);color:var(--blue-deep)}
.header-tools{display:flex;align-items:center;gap:.6rem}
.progress-pill{
  font-size:.82rem;font-weight:700;color:var(--blue-deep);
  background:var(--blue-tint);padding:.35rem .8rem;border-radius:999px;white-space:nowrap;
}

/* ---------- 按钮 ---------- */
.primary,.secondary,.ghost{
  display:inline-flex;align-items:center;justify-content:center;gap:.4rem;
  border-radius:999px;border:0;cursor:pointer;text-decoration:none;
  font:inherit;font-weight:700;transition:transform .16s,box-shadow .16s,background .16s,color .16s;
}
.primary{background:var(--ink);color:#fff;padding:.85rem 1.5rem;box-shadow:0 10px 24px rgba(15,42,51,.18)}
.primary:hover{background:#123a46;transform:translateY(-1px);box-shadow:0 14px 30px rgba(15,42,51,.22)}
.secondary{background:var(--blue-tint);color:var(--blue-deep);padding:.75rem 1.35rem}
.secondary:hover{background:#d5ecf3}
.ghost{background:transparent;border:1px solid var(--line-strong);padding:.4rem .8rem;font-size:.82rem;color:var(--ink-soft)}
.ghost:hover{background:#fff;border-color:var(--muted)}

/* ---------- Hero ---------- */
.hero{
  position:relative;overflow:hidden;
  background:
    radial-gradient(60rem 40rem at 82% -10%, rgba(104,201,224,.30), transparent 60%),
    radial-gradient(48rem 34rem at 8% 110%, rgba(168,214,163,.34), transparent 62%),
    linear-gradient(180deg,#f2f8f8 0%,var(--paper) 78%);
}
.hero::after{
  content:"";position:absolute;inset:auto -18rem -26rem auto;
  width:52rem;height:52rem;border-radius:50%;
  border:1px solid rgba(13,111,143,.14);
  pointer-events:none;
}
.hero-inner{
  position:relative;max-width:var(--maxw);margin:0 auto;
  padding:clamp(48px,7vw,92px) 24px clamp(56px,7vw,96px);
  display:grid;grid-template-columns:1.15fr .85fr;gap:clamp(32px,5vw,72px);align-items:center;
}
.eyebrow{
  color:var(--blue);font-weight:800;letter-spacing:.14em;font-size:.78rem;
  text-transform:uppercase;margin:0 0 .9rem;
}
.hero h1{
  font-size:clamp(2.5rem,5.6vw,4.4rem);
  font-weight:900;line-height:1.08;letter-spacing:-.035em;margin:0 0 1.4rem;
}
.hero h1 em{
  font-style:normal;color:var(--blue);padding:0 .04em;
  background:linear-gradient(180deg,transparent 78%,rgba(104,201,224,.55) 78%,rgba(104,201,224,.55) 96%,transparent 96%);
}
.lead{font-size:clamp(1rem,1.4vw,1.14rem);color:var(--muted);max-width:36rem;margin:0 0 2rem}
.hero-actions{display:flex;align-items:center;gap:1.4rem;flex-wrap:wrap;margin-bottom:2.6rem}
.link-arrow{
  text-decoration:none;font-weight:700;color:var(--blue-deep);
  border-bottom:1px solid rgba(13,111,143,.35);padding-bottom:2px;
}
.link-arrow span{display:inline-block;transition:transform .18s}
.link-arrow:hover span{transform:translateX(4px)}

.hero-facts{display:flex;gap:clamp(18px,3vw,40px);margin:0;flex-wrap:wrap}
.hero-facts div{display:flex;flex-direction:column}
.hero-facts dt{font-size:1.7rem;font-weight:900;letter-spacing:-.03em;color:var(--ink);line-height:1.1}
.hero-facts dd{margin:.3rem 0 0;font-size:.84rem;color:var(--muted)}

.hero-visual{display:flex;justify-content:center}
.drop-card{
  width:min(100%,340px);background:var(--white);border:1px solid var(--line);
  border-radius:26px;padding:28px 26px 22px;box-shadow:var(--shadow-md);
  position:relative;
}
.drop-art{display:block;margin:0 auto 6px;width:100%;max-width:240px;height:auto}
.model-steps{list-style:none;padding:0;margin:12px 0 0;display:grid;gap:0}
.model-steps li{
  display:flex;align-items:center;gap:.7rem;font-size:.86rem;font-weight:600;color:var(--ink-soft);
  padding:.55rem 0;border-top:1px dashed var(--line);
}
.model-steps span{
  font-size:.7rem;font-weight:800;color:var(--blue);background:var(--blue-tint);
  border-radius:6px;padding:.1rem .4rem;letter-spacing:.04em;
}

/* ---------- 区块骨架 ---------- */
.section{max-width:var(--maxw);margin:0 auto;padding:clamp(56px,7vw,92px) 24px;scroll-margin-top:calc(var(--header-h) + 12px)}
.band{background:var(--white);max-width:none;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.band > *{max-width:var(--maxw);margin-left:auto;margin-right:auto}
.section-head{margin-bottom:clamp(28px,4vw,44px)}
.section-head h2{font-size:clamp(1.7rem,3.2vw,2.5rem);font-weight:800;letter-spacing:-.025em;max-width:44rem}
.section-note{margin:.9rem 0 0;color:var(--muted);font-size:.95rem;max-width:44rem}

/* ---------- 挑战区 ---------- */
.brief-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:clamp(24px,4vw,44px);align-items:start}
.driving{
  margin:0;padding:1.6rem 1.7rem;border-radius:var(--radius);
  background:linear-gradient(135deg,#eef8fa,#eaf3ec);
  border:1px solid #d8e9e9;border-left:5px solid var(--blue);
  font-size:1.08rem;font-weight:600;line-height:1.8;color:var(--ink-soft);
}
.brief-side h3{font-size:1rem;color:var(--blue-deep);margin-bottom:.5rem}
.brief-side p{color:var(--muted);font-size:.95rem}
.privacy{background:#fff8e8;border:1px solid #f0e2c4;border-radius:12px;padding:.8rem 1rem;font-size:.86rem!important;color:#6b5730!important}
.metrics{
  display:grid;grid-template-columns:repeat(4,1fr);gap:1rem;margin-top:clamp(24px,4vw,40px);
}
.metrics div{
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius-sm);
  padding:1rem 1.1rem;display:flex;align-items:baseline;gap:.6rem;
}
.metrics strong{font-size:1.6rem;font-weight:900;color:var(--blue);letter-spacing:-.03em}
.metrics span{font-size:.85rem;color:var(--muted)}

/* ---------- 目标 ---------- */
.goals-grid{display:grid;grid-template-columns:1fr 1fr;gap:1.2rem}
.goals-grid article{
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius);
  padding:1.5rem 1.6rem;box-shadow:var(--shadow-sm);
}
.goals-grid h3{display:flex;align-items:center;gap:.5rem;font-size:1.02rem;color:var(--ink);margin-bottom:.9rem}
.dot{width:9px;height:9px;border-radius:50%;background:var(--blue);display:inline-block}
.dot.green{background:var(--green)}
.goals-grid ul{padding-left:1.15rem;margin:0;display:grid;gap:.45rem}
.goals-grid li{font-size:.94rem;color:var(--ink-soft)}

.plan-strip{display:grid;grid-template-columns:1.15fr .85fr;gap:1.2rem;margin-top:1.2rem}
.plan-item{
  background:var(--green-tint);border:1px solid #d7e8da;border-radius:var(--radius);
  padding:1.2rem 1.4rem;
}
.plan-item:nth-child(2){background:var(--blue-tint);border-color:#cfe7ee}
.plan-label{
  display:inline-block;font-size:.74rem;font-weight:800;letter-spacing:.1em;
  color:var(--green);text-transform:uppercase;margin-bottom:.4rem;
}
.plan-item:nth-child(2) .plan-label{color:var(--blue)}
.plan-item p{font-size:.92rem;color:var(--ink-soft)}

/* ---------- 任务导航 ---------- */
.task-nav{display:grid;grid-template-columns:repeat(4,1fr);gap:1rem;align-items:stretch}
.stage{
  display:flex;flex-direction:column;gap:.6rem;
  background:#f8fbfa;border:1px solid var(--line);border-radius:16px;padding:.85rem;
}
.stage h3{
  font-size:.78rem;font-weight:800;letter-spacing:.08em;color:var(--green);
  display:flex;align-items:center;gap:.45rem;margin:0 0 .2rem;text-transform:uppercase;
}
.stage h3 > span{
  font-size:.68rem;background:var(--green-tint);color:var(--green);
  border-radius:5px;padding:.08rem .35rem;
}
.task-nav a{
  display:block;position:relative;text-decoration:none;
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius-sm);
  padding:.95rem 1rem .95rem 1rem;transition:transform .18s,box-shadow .18s,border-color .18s;
}
.task-nav a:hover{transform:translateY(-2px);box-shadow:var(--shadow-sm);border-color:var(--line-strong)}
.task-nav .num{font-size:.7rem;font-weight:800;color:var(--blue);letter-spacing:.06em}
.task-nav .t{display:block;font-weight:700;font-size:.92rem;line-height:1.5;margin:.15rem 0 .45rem}
.task-nav small{display:block;font-size:.74rem;color:var(--muted)}
.task-nav a.done{background:var(--green-tint);border-color:#cbdfd0}
.task-nav a.done::after{
  content:"✓";position:absolute;top:.7rem;right:.8rem;width:18px;height:18px;
  display:grid;place-items:center;border-radius:50%;background:var(--green);color:#fff;
  font-size:.68rem;font-weight:800;
}

/* ---------- 任务区块 ---------- */
.task{
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow-sm);margin:0 auto 1.4rem;
  max-width:calc(var(--maxw) - 48px);padding:clamp(28px,4vw,44px);
}
.task-head{display:flex;align-items:baseline;gap:1rem;flex-wrap:wrap;margin-bottom:1.2rem}
.task-badge{
  font-size:.74rem;font-weight:800;letter-spacing:.1em;color:var(--blue-deep);
  background:var(--blue-tint);border-radius:999px;padding:.25rem .7rem;text-transform:uppercase;
}
.task-head h2{font-size:clamp(1.35rem,2.2vw,1.85rem);flex:1 1 auto}
.task-time{font-size:.8rem;color:var(--muted);white-space:nowrap}
.situation{
  background:var(--green-tint);border-left:4px solid var(--green);border-radius:10px;
  padding:.9rem 1.1rem;margin:0 0 1.2rem;font-size:.94rem;color:var(--ink-soft);
}
.situation strong{color:var(--green);font-weight:800}
.lead-sm{font-size:.94rem;color:var(--muted)}

.two-col{display:grid;grid-template-columns:1fr 1fr;gap:1.2rem;margin-bottom:1.2rem}
.two-col h3{font-size:.95rem;color:var(--blue-deep);margin-bottom:.4rem}
.two-col p{font-size:.92rem;color:var(--ink-soft)}
.two-col textarea{
  width:100%;border:1px solid var(--line-strong);border-radius:10px;padding:.7rem .8rem;
  font:inherit;font-size:.92rem;color:var(--ink);background:#fdfdfb;resize:vertical;
}

.task-blocks{display:grid;grid-template-columns:1fr 1fr;gap:1.1rem;margin-top:1.2rem}
.block{background:#fafbf9;border:1px solid var(--line);border-radius:var(--radius-sm);padding:1.1rem 1.2rem}
.block h3{font-size:.92rem;color:var(--blue-deep);margin-bottom:.5rem}
.block ol,.block ul{padding-left:1.2rem;display:grid;gap:.3rem}
.block li{font-size:.9rem;color:var(--ink-soft)}

.complete{
  display:flex;align-items:center;gap:.6rem;margin-top:1.4rem;padding-top:1.1rem;
  border-top:1px dashed var(--line-strong);font-size:.9rem;font-weight:600;color:var(--ink-soft);cursor:pointer;
}
.complete input{width:18px;height:18px;accent-color:var(--green);cursor:pointer}

/* ---------- 表单 ---------- */
.tool-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:.9rem 1rem;margin:1rem 0 .4rem}
.tool-grid label{display:grid;gap:.35rem;font-size:.84rem;font-weight:600;color:var(--muted)}
.tool-grid .wide{grid-column:1/-1}
.tool-grid button{justify-self:start;margin-top:.3rem}
input[type=number],input[type=text],input:not([type]),select,textarea{
  font:inherit;font-size:.92rem;font-weight:400;color:var(--ink);
  background:#fdfdfb;border:1px solid var(--line-strong);border-radius:10px;
  padding:.6rem .7rem;width:100%;transition:border-color .16s,box-shadow .16s;
}
input[type=number]:focus,input[type=text]:focus,input:not([type]):focus,select:focus,textarea:focus{
  border-color:var(--blue);box-shadow:0 0 0 3px rgba(13,111,143,.14);outline:none;
}
fieldset{border:1px solid var(--line);border-radius:var(--radius-sm);padding:1rem 1.1rem;margin:0}
legend{font-size:.84rem;font-weight:700;color:var(--blue-deep);padding:0 .4rem}
fieldset{display:grid;grid-template-columns:repeat(5,1fr);gap:.8rem}
fieldset label{display:grid;gap:.3rem;font-size:.8rem;color:var(--muted);font-weight:600}

.solution-form{display:grid;grid-template-columns:1fr 1fr;gap:1.1rem}
.solution{background:#fafbf9;border:1px solid var(--line);border-radius:var(--radius-sm);padding:1.1rem 1.2rem;display:grid;grid-template-columns:1fr 1fr;gap:.7rem}
.solution h3{grid-column:1/-1;font-size:.95rem;color:var(--blue-deep)}
.solution label{display:grid;gap:.3rem;font-size:.78rem;color:var(--muted);font-weight:600}
.solution-form fieldset{grid-column:1/-1}
.solution-form > button{grid-column:1/-1;justify-self:start}

/* ---------- 结果与提示 ---------- */
.result{
  margin:1rem 0 0;padding:1rem 1.2rem;border-radius:var(--radius-sm);
  background:var(--blue-tint);border:1px solid #cfe7ee;border-left:4px solid var(--blue);
  font-size:.92rem;color:var(--ink-soft);line-height:1.7;
}
.result:empty{display:none}
.result strong{color:var(--blue-deep)}
.result.error{background:#fdf0ed;border-color:#f0cfc7;border-left-color:var(--danger);color:#7d3326}
.result.error strong{color:var(--danger)}
.result small{color:var(--muted);font-size:.82rem}
.note{font-size:.85rem;color:var(--muted);margin-top:.7rem}
.checklist{margin-top:1rem;background:#fafbf9;border:1px solid var(--line);border-radius:var(--radius-sm);padding:.8rem 1.1rem}
.checklist summary{cursor:pointer;font-weight:700;font-size:.9rem;color:var(--blue-deep)}
.checklist ul{margin:.6rem 0 0;padding-left:1.15rem;display:grid;gap:.3rem;font-size:.88rem;color:var(--ink-soft)}

/* ---------- 资源 ---------- */
.resource-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1.1rem}
.resource-grid article{
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius);
  padding:1.3rem 1.4rem;display:flex;flex-direction:column;gap:.4rem;
}
.resource-grid article.tool{border-color:#cfe7ee;background:linear-gradient(180deg,#fbfeff,#fff)}
.resource-grid h3{font-size:.98rem;color:var(--blue-deep)}
.resource-grid p{font-size:.88rem;color:var(--ink-soft)}
.resource-grid button{margin-top:auto;align-self:flex-start}
.convert-form{display:grid;grid-template-columns:1fr auto;gap:.6rem;margin:.4rem 0 0}
.convert-form label{display:grid;gap:.25rem;font-size:.78rem;color:var(--muted);font-weight:600}
.convert-form button{grid-column:1/-1;justify-self:start;padding:.6rem 1.1rem;font-size:.85rem}

/* ---------- 评价 ---------- */
.rubric-form{display:grid;grid-template-columns:repeat(2,1fr);gap:1.1rem 1.6rem;background:var(--white);border:1px solid var(--line);border-radius:var(--radius);padding:1.5rem 1.6rem}
.rubric-form label{
  display:grid;grid-template-columns:1fr 2.6rem;grid-template-rows:auto auto;
  align-items:center;gap:.35rem .7rem;font-size:.86rem;font-weight:600;color:var(--muted);
}
.rubric-form label > input[type=range]{grid-column:1;grid-row:2;width:100%;margin:0;accent-color:var(--blue)}
.rubric-form label > output{
  grid-column:2;grid-row:2;font-weight:800;color:var(--blue-deep);font-size:.9rem;
  text-align:center;background:var(--blue-tint);border-radius:8px;padding:.15rem .2rem;
}
.rubric-form label.wide{grid-column:1/-1;grid-template-columns:1fr}
.rubric-form label.wide > textarea{grid-column:1/-1;grid-row:2}

.peer-form,.teacher-form{
  display:grid;grid-template-columns:repeat(2,1fr);gap:1.1rem 1.6rem;
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius);padding:1.5rem 1.6rem;
}
.peer-form label,.teacher-form label{
  display:grid;grid-template-columns:1fr 2.6rem;grid-template-rows:auto auto;
  align-items:center;gap:.35rem .7rem;font-size:.86rem;font-weight:600;color:var(--muted);
}
.peer-form label > input[type=range]{grid-column:1;grid-row:2;width:100%;margin:0;accent-color:var(--green)}
.peer-form label > output{
  grid-column:2;grid-row:2;font-weight:800;color:var(--green);font-size:.9rem;
  text-align:center;background:var(--green-tint);border-radius:8px;padding:.15rem .2rem;
}
.peer-form label > input:not([type=range]),
.peer-form label > textarea,
.teacher-form label > select,
.teacher-form label > textarea{grid-column:1/-1;grid-row:2}
.peer-form label.wide,.teacher-form label.wide{grid-column:1/-1;grid-template-columns:1fr}
.peer-form button,.teacher-form button{grid-column:1/-1;justify-self:start}

/* ---------- AI 引导 ---------- */
.coach{background:linear-gradient(180deg,#eef7fa,#f6f5ef);border-top:1px solid var(--line);border-bottom:1px solid var(--line);max-width:none}
.coach > *{max-width:var(--maxw);margin-left:auto;margin-right:auto}
.coach form{
  display:grid;grid-template-columns:.55fr 1.45fr;gap:1rem;align-items:start;
  background:var(--white);border:1px solid var(--line);border-radius:var(--radius);padding:1.5rem 1.6rem;
}
.coach form label{display:grid;gap:.4rem;font-size:.84rem;font-weight:600;color:var(--muted)}
.coach form button{grid-column:1/-1;justify-self:start}
.coach-history{display:grid;gap:.8rem}
.coach-item{background:var(--white);border:1px solid var(--line);border-radius:var(--radius-sm);padding:.9rem 1.1rem}
.coach-q{font-weight:700;font-size:.9rem;margin:0 0 .25rem;color:var(--ink)}
.coach-a{font-size:.9rem;margin:0;color:var(--ink-soft)}
.coach-item time{display:block;font-size:.74rem;color:var(--muted);margin-top:.4rem}

/* ---------- 记录 ---------- */
.actions{display:flex;gap:.8rem;flex-wrap:wrap}

/* ---------- 拓展 ---------- */
.tiers{display:grid;grid-template-columns:repeat(3,1fr);gap:1.1rem;margin-bottom:2rem}
.tier{background:var(--white);border:1px solid var(--line);border-top:4px solid var(--line-strong);border-radius:var(--radius);padding:1.3rem 1.4rem}
.tier.base{border-top-color:var(--green)}
.tier.advance{border-top-color:var(--blue)}
.tier.challenge{border-top-color:var(--amber)}
.tier h3{font-size:.98rem;margin-bottom:.6rem}
.tier ul{padding-left:1.15rem;display:grid;gap:.3rem}
.tier li{font-size:.9rem;color:var(--ink-soft)}
.cross-list{padding-left:1.15rem;display:grid;gap:.4rem;font-size:.92rem;color:var(--ink-soft)}
.cross-list strong{color:var(--blue-deep)}

/* ---------- 页脚 ---------- */
.site-footer{background:var(--ink);color:#c8d8d7;padding:clamp(40px,5vw,64px) 24px;margin-top:0}
.footer-inner{
  max-width:var(--maxw);margin:0 auto;display:grid;
  grid-template-columns:1.2fr 1fr;gap:1.6rem 2.4rem;font-size:.86rem;
}
.footer-title{font-size:1.05rem;font-weight:800;color:#fff;margin-bottom:.3rem}
.footer-inner .fine{grid-column:1/-1;border-top:1px solid rgba(255,255,255,.12);padding-top:1.2rem;color:#8fa9a6;font-size:.78rem}

/* ---------- 通用 ---------- */
.mt{margin-top:2.2rem}
h3.mt + .peer-form,h3.mt + .teacher-form{margin-top:1rem}

/* ---------- 响应式 ---------- */
@media (max-width:980px){
  .hero-inner{grid-template-columns:1fr;gap:40px}
  .hero-visual{justify-content:flex-start}
  .drop-card{width:min(100%,300px)}
  .brief-grid,.plan-strip{grid-template-columns:1fr}
  .task-nav{grid-template-columns:1fr 1fr}
  .resource-grid{grid-template-columns:1fr 1fr}
  .goals-grid{grid-template-columns:1fr}
  .metrics{grid-template-columns:1fr 1fr}
  .coach form{grid-template-columns:1fr}
  .footer-inner{grid-template-columns:1fr}
}
@media (max-width:760px){
  .site-nav{display:none}
  .hero-visual{display:none}
  .header-inner{gap:12px;padding:0 16px}
  .section{padding-left:16px;padding-right:16px}
  .task{max-width:none;margin-left:0;margin-right:0;border-radius:16px}
  .two-col,.task-blocks,.solution-form,.rubric-form,.peer-form,.teacher-form{grid-template-columns:1fr}
  .tool-grid{grid-template-columns:1fr 1fr}
  fieldset{grid-template-columns:1fr 1fr}
  .solution{grid-template-columns:1fr}
  .tiers{grid-template-columns:1fr}
  .task-nav{grid-template-columns:1fr}
  .brand-text{font-size:.92rem}
  .progress-pill{font-size:.76rem;padding:.3rem .6rem}
  .hero-facts{gap:20px 28px}
}
@media (max-width:520px){
  .metrics{grid-template-columns:1fr}
  .resource-grid{grid-template-columns:1fr}
  .header-tools .ghost{display:none}
}

/* ---------- 动效偏好 ---------- */
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.001ms!important;transition-duration:.001ms!important}
  html{scroll-behavior:auto}
}

/* ---------- 打印 ---------- */
@media print{
  .site-header,.site-nav,.hero-visual,.hero-actions,.actions,.coach form,.resource-grid button,
  .peer-form,.teacher-form,.convert-form,.skip-link,.task-nav{display:none!important}
  body{background:#fff;font-size:12pt}
  .hero,.band,.coach{background:#fff}
  .task,.goals-grid article,.tier,.resource-grid article{box-shadow:none;border:1px solid #999;break-inside:avoid}
  .site-footer{background:#fff;color:#333}
  a{text-decoration:none;color:#000}
}