/* 《AI 小创客》统一样式 —— HelloCode 蓝黄、投屏友好、低龄大字大按钮 */
:root{
  --blue:#3498db; --blue-deep:#2563eb; --blue-dark:#1d4ed8;
  --yellow:#facc15; --yellow-deep:#f59e0b;
  --green:#27ae60; --red:#ef476f; --purple:#8338ec;
  --ink:#2c3e50; --muted:#6b7280; --bg:#f5f7fa; --card:#ffffff;
  --shadow:0 6px 24px rgba(0,0,0,.10); --shadow-sm:0 2px 8px rgba(0,0,0,.08);
  --radius:18px;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  font-family:"Microsoft YaHei","PingFang SC",sans-serif;
  background:var(--bg); color:var(--ink); line-height:1.6;
}
button{font-family:inherit}
a{color:inherit;text-decoration:none}

/* ===== 顶栏 ===== */
.topbar{
  display:flex;align-items:center;gap:14px;
  padding:14px 26px;background:#fff;box-shadow:var(--shadow-sm);
  position:sticky;top:0;z-index:50;
}
.topbar img{height:46px;width:auto}
.topbar .brand{font-weight:800;font-size:20px;color:var(--blue-deep)}
.topbar .brand small{display:block;font-size:12px;color:var(--muted);font-weight:400}
.topbar .spacer{flex:1}
.topbar .home-link{
  background:var(--blue);color:#fff;padding:8px 16px;border-radius:999px;
  font-size:15px;font-weight:700;
}
.topbar .home-link:hover{background:var(--blue-deep)}

/* ===== 首页 ===== */
.hero{
  text-align:center;padding:56px 20px 30px;
  background:linear-gradient(135deg,#eaf4ff,#fff7e0);
}
.hero h1{font-size:46px;font-weight:900;color:var(--blue-deep);letter-spacing:1px}
.hero .tag{display:inline-block;margin-top:8px;background:var(--yellow);
  color:#7a4a00;font-weight:800;padding:6px 18px;border-radius:999px;font-size:16px}
.hero p{margin-top:16px;color:var(--muted);font-size:18px}

.lesson-grid{
  max-width:1100px;margin:34px auto;padding:0 20px;
  display:grid;grid-template-columns:repeat(3,1fr);gap:22px;
}
.lesson-card{
  background:var(--card);border-radius:var(--radius);padding:26px 22px;
  box-shadow:var(--shadow-sm);transition:transform .2s,box-shadow .2s;
  border:3px solid transparent;position:relative;display:block;
}
.lesson-card:hover{transform:translateY(-6px);box-shadow:var(--shadow);border-color:var(--blue)}
.lesson-card .no{font-size:14px;color:var(--muted);font-weight:700}
.lesson-card .emoji{font-size:54px;line-height:1;margin:6px 0 10px}
.lesson-card h3{font-size:23px;color:var(--ink)}
.lesson-card .sub{color:var(--muted);margin-top:6px;font-size:15px}
.lesson-card .badge{
  position:absolute;top:16px;right:16px;font-size:12px;font-weight:800;
  padding:4px 10px;border-radius:999px;
}
.badge.ready{background:#e6f7ee;color:var(--green)}
.badge.soon{background:#f0f0f3;color:var(--muted)}
.lesson-card.soon{opacity:.7}

/* ===== 课程页：分页式 slides ===== */
.lesson-wrap{max-width:960px;margin:0 auto;padding:24px 20px 120px}
.lesson-head{text-align:center;margin:10px 0 18px}
.lesson-head .no{color:var(--blue-deep);font-weight:800;font-size:16px}
.lesson-head h1{font-size:34px;font-weight:900;margin-top:4px}
.lesson-head .sub{color:var(--muted);font-size:17px;margin-top:4px}

.slide{
  display:none;background:var(--card);border-radius:var(--radius);
  padding:38px 40px;box-shadow:var(--shadow);min-height:60vh;
  animation:fade .35s ease;
}
.slide.active{display:block}
@keyframes fade{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:none}}
.slide h2{font-size:30px;color:var(--blue-deep);margin-bottom:14px}
.slide h2 .step{
  display:inline-block;background:var(--yellow);color:#7a4a00;
  font-size:15px;padding:2px 12px;border-radius:999px;margin-right:10px;vertical-align:middle}
.slide p{font-size:19px;margin:12px 0}
.slide .big{font-size:23px;font-weight:700}
.slide ul{font-size:19px;margin:12px 0 12px 26px}
.slide li{margin:8px 0}
.hl{color:var(--red);font-weight:800}
.hl-blue{color:var(--blue-deep);font-weight:800}
.note{background:#fff8e1;border-left:6px solid var(--yellow);
  padding:14px 18px;border-radius:10px;font-size:17px;margin:16px 0}

/* 卡片网格（找一找 AI 等） */
.flip-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin:18px 0}
.flip{
  background:#eef4ff;border-radius:14px;padding:22px 10px;text-align:center;
  cursor:pointer;transition:.2s;border:3px solid transparent;user-select:none}
.flip:hover{border-color:var(--blue)}
.flip .ic{font-size:46px}
.flip .lb{margin-top:8px;font-weight:700;font-size:16px}
.flip.on{background:#e6f7ee;border-color:var(--green)}
.flip .ans{display:none;font-size:14px;color:var(--green);margin-top:6px}
.flip.on .ans{display:block}

/* 通用大按钮 */
.btn{
  background:var(--blue);color:#fff;border:none;border-radius:14px;
  padding:14px 28px;font-size:19px;font-weight:800;cursor:pointer;transition:.15s;
  box-shadow:0 4px 0 var(--blue-dark)}
.btn:hover{background:var(--blue-deep)}
.btn:active{transform:translateY(3px);box-shadow:0 1px 0 var(--blue-dark)}
.btn.yellow{background:var(--yellow);color:#7a4a00;box-shadow:0 4px 0 var(--yellow-deep)}
.btn.yellow:hover{background:#fbbf24}
.btn.gray{background:#e5e7eb;color:#374151;box-shadow:0 4px 0 #cbd1d9}
.btn:disabled{opacity:.5;cursor:not-allowed}

input[type=text],textarea,.input{
  font-family:inherit;font-size:18px;padding:12px 16px;border:2px solid #d1d9e6;
  border-radius:12px;width:100%;outline:none}
input[type=text]:focus,textarea:focus{border-color:var(--blue)}

/* 互动盒 */
.play{background:#f0f6ff;border:2px dashed var(--blue);border-radius:16px;
  padding:22px;margin:18px 0}
.play .tip{font-size:15px;color:var(--blue-deep);font-weight:700;margin-bottom:10px}
.row{display:flex;gap:12px;flex-wrap:wrap;align-items:center}
.output{background:#fff;border-radius:12px;padding:18px;margin-top:14px;
  font-size:20px;min-height:54px;box-shadow:var(--shadow-sm)}
.caret::after{content:"▋";color:var(--blue);animation:blink 1s step-end infinite}
@keyframes blink{50%{opacity:0}}

/* 概率条 */
.probs{margin-top:10px}
.probrow{display:flex;align-items:center;gap:10px;margin:8px 0}
.probrow .w{width:90px;font-size:18px;font-weight:700}
.probrow .bar{height:26px;border-radius:8px;background:var(--blue);transition:width .8s}
.probrow .pct{font-size:15px;color:var(--muted)}

/* 出图 */
.imgbox{margin-top:14px;text-align:center}
.imgbox img{max-width:340px;border-radius:14px;box-shadow:var(--shadow)}
.spinner{display:inline-block;width:34px;height:34px;border:4px solid #cfe2ff;
  border-top-color:var(--blue);border-radius:50%;animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}

/* 底部翻页条 */
.navbar{
  position:fixed;left:0;right:0;bottom:0;background:#fff;box-shadow:0 -2px 12px rgba(0,0,0,.08);
  display:flex;align-items:center;justify-content:center;gap:18px;padding:12px;z-index:40}
.navbar .dots{display:flex;gap:8px}
.navbar .dot{width:12px;height:12px;border-radius:50%;background:#d1d9e6;cursor:pointer}
.navbar .dot.on{background:var(--blue);transform:scale(1.25)}
.navbar .pginfo{font-size:15px;color:var(--muted);min-width:64px;text-align:center}

.badge-tip{display:inline-block;background:#e6f7ee;color:var(--green);
  font-weight:800;padding:4px 12px;border-radius:999px;font-size:14px;margin-left:8px}

/* 老师提示条（含时长，投屏时老师看，醒目但不喧宾夺主） */
.teacher{
  background:#eef2ff;border:2px dashed #818cf8;border-radius:12px;
  padding:12px 16px;margin:16px 0;font-size:15px;color:#3730a3}
.teacher b{color:#4338ca}
.teacher .clock{display:inline-block;background:#4338ca;color:#fff;
  font-weight:800;padding:2px 12px;border-radius:999px;margin-right:8px;font-size:14px}
/* 环节大标签 */
.phase-tag{display:inline-block;background:var(--purple);color:#fff;
  font-weight:800;font-size:14px;padding:3px 14px;border-radius:999px;margin-bottom:10px}
/* 进阶（照顾高年级） */
.plus{background:#fff4ec;border-left:6px solid var(--yellow-deep);
  padding:12px 16px;border-radius:10px;font-size:16px;margin:14px 0}
.plus b{color:var(--yellow-deep)}
/* 计分板 */
.score{display:flex;gap:16px;flex-wrap:wrap;margin:14px 0}
.score .team{background:#fff;border-radius:14px;padding:14px 22px;box-shadow:var(--shadow-sm);
  text-align:center;min-width:120px}
.score .team .name{font-weight:800;font-size:17px}
.score .team .pt{font-size:40px;font-weight:900;color:var(--blue-deep);line-height:1.1}
.score .team button{margin-top:6px;font-size:14px;padding:4px 12px;border-radius:8px;
  border:none;background:var(--green);color:#fff;cursor:pointer;font-weight:700}
/* 任务清单/闯关 */
.quest{list-style:none;margin:14px 0;padding:0}
.quest li{background:#fff;border-radius:12px;padding:12px 16px;margin:8px 0;
  box-shadow:var(--shadow-sm);font-size:17px;cursor:pointer;display:flex;align-items:center;gap:10px}
.quest li .box{width:24px;height:24px;border:2px solid var(--blue);border-radius:6px;flex:0 0 auto}
.quest li.done{background:#e6f7ee}
.quest li.done .box{background:var(--green);border-color:var(--green)}
.quest li.done .box::after{content:"✓";color:#fff;font-weight:900;display:block;text-align:center;line-height:22px}
.quest li.done .t{text-decoration:line-through;color:var(--muted)}
.divider{text-align:center;color:#b0b8c4;font-size:15px;margin:22px 0;font-weight:700}

/* 登录卡片（大方好看） */
.login-card{
  max-width:440px;margin:24px auto 70px;padding:36px 36px 30px;
  background:#fff;border-radius:22px;box-shadow:var(--shadow);
}
.field-label{display:block;font-size:16px;font-weight:800;color:var(--ink);
  margin:16px 0 8px}
.field{
  width:100%;font-size:20px;padding:16px 18px;border:2px solid #d8e0ec;
  border-radius:14px;background:#f8fafc;transition:.15s;outline:none}
.field:focus{border-color:var(--blue);background:#fff;box-shadow:0 0 0 4px rgba(52,152,219,.15)}
.field::placeholder{color:#b6c0cf}

@media (max-width:820px){
  .login-card{margin:18px 16px 50px;padding:26px 22px}
  .lesson-grid{grid-template-columns:1fr 1fr}
  .flip-grid{grid-template-columns:1fr 1fr}
  .hero h1{font-size:34px}.slide{padding:24px}
}