/* ============================================
   Scratch Bug侦探学院 V3 — 儿童Scratch学习平台
   风格：蓝天梦幻 / 玻璃拟态 / 卡通游戏化
   ============================================ */

:root {
  --sky-top: #5BA4F0;
  --sky-mid: #87C8F5;
  --sky-bot: #D2EAFB;
  --blue: #4C97FF;
  --blue-dark: #3373CC;
  --blue-light: #A8D1FF;
  --yellow: #FFB830;
  --yellow-dark: #D6950A;
  --orange: #FF8C1A;
  --orange-dark: #D0680A;
  --purple: #8559E6;
  --purple-dark: #6A3FD0;
  --green: #4ECB71;
  --green-dark: #35A052;
  --pink: #FF6B9D;
  --red: #FF6680;
  --red-light: #FFA0B4;
  --card-bg: rgba(255,255,255,0.92);
  --text: #2C2C3A;
  --text-light: #6B6B80;
  --text-white: #FFFFFF;
  --glass: rgba(255,255,255,0.75);
  --glass-border: rgba(255,255,255,0.5);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
  --shadow: 0 8px 28px rgba(0,0,0,0.10);
  --shadow-lg: 0 16px 48px rgba(0,0,0,0.14);
  --shadow-glow-blue: 0 8px 32px rgba(76,151,255,0.3);
  --shadow-glow-yellow: 0 8px 32px rgba(255,184,48,0.3);
  --radius-xl: 28px;
  --radius-lg: 22px;
  --radius: 16px;
  --radius-sm: 12px;
  --font: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============ RESET ============ */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;scroll-behavior:smooth}
body{
  font-family:var(--font);
  color:var(--text);
  min-height:100vh;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
  /* 蓝天渐变背景 */
  background: linear-gradient(180deg,
    #5BA4F0 0%,
    #74B8F3 15%,
    #8ECAF7 30%,
    #A9D7F9 45%,
    #C2E2FB 60%,
    #D6EBFC 75%,
    #E5F1FD 90%,
    #F0F6FE 100%
  );
  background-attachment: fixed;
}

/* ============ 云朵系统 ============ */
.clouds-layer{
  position:fixed;inset:0;pointer-events:none;z-index:0;overflow:hidden;
}
.cloud{
  position:absolute;
  background:white;
  border-radius:50%;
  opacity:0.85;
}
.cloud::before,.cloud::after{
  content:'';position:absolute;
  background:white;border-radius:50%;
}
.cloud-1{
  width:180px;height:60px;
  top:8%;left:5%;
  border-radius:60px;
  animation:cloudDrift 28s linear infinite;
}
.cloud-1::before{
  width:80px;height:80px;
  top:-40px;left:30px;
}
.cloud-1::after{
  width:100px;height:70px;
  top:-30px;left:70px;
}
.cloud-2{
  width:140px;height:48px;
  top:14%;left:65%;
  border-radius:48px;
  animation:cloudDrift 22s linear infinite;
  animation-delay:-8s;
}
.cloud-2::before{
  width:60px;height:60px;
  top:-30px;left:25px;
}
.cloud-2::after{
  width:75px;height:55px;
  top:-22px;left:55px;
}
.cloud-3{
  width:200px;height:64px;
  top:25%;left:30%;
  border-radius:64px;
  animation:cloudDrift 32s linear infinite;
  animation-delay:-15s;
  opacity:0.7;
}
.cloud-3::before{
  width:90px;height:85px;
  top:-42px;left:40px;
}
.cloud-3::after{
  width:110px;height:75px;
  top:-32px;left:80px;
}
.cloud-4{
  width:120px;height:40px;
  top:6%;left:80%;
  border-radius:40px;
  animation:cloudDrift 25s linear infinite;
  animation-delay:-4s;
  opacity:0.8;
}
.cloud-4::before{
  width:50px;height:50px;
  top:-28px;left:20px;
}
.cloud-4::after{
  width:60px;height:45px;
  top:-20px;left:50px;
}
.cloud-5{
  width:160px;height:52px;
  top:35%;left:72%;
  border-radius:52px;
  animation:cloudDrift 30s linear infinite;
  animation-delay:-20s;
  opacity:0.65;
}
.cloud-5::before{
  width:70px;height:70px;
  top:-35px;left:30px;
}
.cloud-5::after{
  width:85px;height:60px;
  top:-28px;left:65px;
}
@keyframes cloudDrift{
  0%{transform:translateX(0)}
  100%{transform:translateX(120px)}
}

/* ============ 装饰元素层 ============ */
.decorations-layer{
  position:fixed;inset:0;pointer-events:none;z-index:0;overflow:hidden;
}
.deco{
  position:absolute;
  font-size:1.8rem;
  opacity:0.2;
  animation:floatDeco 6s ease-in-out infinite;
}
.deco:nth-child(1){top:12%;left:8%;animation-delay:0s;font-size:2rem;opacity:0.18}
.deco:nth-child(2){top:22%;left:75%;animation-delay:-1.2s;font-size:1.6rem;opacity:0.22}
.deco:nth-child(3){top:45%;left:4%;animation-delay:-2.5s;font-size:2.2rem;opacity:0.15}
.deco:nth-child(4){top:55%;left:82%;animation-delay:-3.8s;font-size:1.8rem;opacity:0.2}
.deco:nth-child(5){top:68%;left:18%;animation-delay:-1.5s;font-size:1.5rem;opacity:0.18}
.deco:nth-child(6){top:78%;left:60%;animation-delay:-4.2s;font-size:2rem;opacity:0.16}
.deco:nth-child(7){top:88%;left:35%;animation-delay:-0.8s;font-size:1.7rem;opacity:0.2}
.deco:nth-child(8){top:32%;left:48%;animation-delay:-5s;font-size:1.4rem;opacity:0.14}
@keyframes floatDeco{
  0%,100%{transform:translateY(0) rotate(0deg)}
  50%{transform:translateY(-18px) rotate(8deg)}
}

/* ============ 玻璃拟态导航栏 ============ */
.navbar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:10px 28px;
  background:rgba(255,255,255,0.55);
  backdrop-filter:blur(20px);
  -webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid rgba(255,255,255,0.6);
  position:sticky;
  top:0;
  z-index:100;
  flex-wrap:wrap;
  gap:10px;
}
.nav-logo{
  display:flex;
  align-items:center;
  gap:10px;
  font-size:1.3rem;
  font-weight:900;
  color:var(--blue);
  text-decoration:none;
  transition:var(--transition);
}
.nav-logo:hover{transform:scale(1.05)}
.nav-logo .logo-icon{
  font-size:2rem;
  animation:logoBounce 2.5s ease-in-out infinite;
}
@keyframes logoBounce{
  0%,100%{transform:translateY(0)}
  30%{transform:translateY(-8px)}
  60%{transform:translateY(-3px)}
}
.nav-links{display:flex;gap:4px;flex-wrap:wrap}
.nav-links a{
  text-decoration:none;
  color:var(--text);
  font-weight:700;
  padding:10px 20px;
  border-radius:30px;
  transition:var(--transition);
  font-size:0.92rem;
  white-space:nowrap;
}
.nav-links a:hover{
  background:rgba(255,255,255,0.7);
  transform:translateY(-2px);
  box-shadow:var(--shadow-sm);
}
.nav-links a.active{
  background:var(--blue);
  color:white;
  box-shadow:0 6px 20px rgba(76,151,255,0.35);
}

/* ============ 容器 ============ */
.container{
  max-width:1060px;
  margin:0 auto;
  padding:24px 24px 60px;
  position:relative;
  z-index:1;
}

/* ============ 卡片基础 ============ */
.card{
  background:var(--card-bg);
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  border-radius:var(--radius-lg);
  padding:26px 26px;
  box-shadow:var(--shadow);
  transition:var(--transition);
  margin-bottom:18px;
  border:1px solid var(--glass-border);
}
.card:hover{
  box-shadow:var(--shadow-lg);
  transform:translateY(-3px);
}
.card-title{
  font-size:1.25rem;
  font-weight:800;
  margin-bottom:14px;
  color:var(--text);
  display:flex;
  align-items:center;
  gap:8px;
}

/* ============ 按钮系统 ============ */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:14px 32px;
  border-radius:50px;
  font-size:1rem;
  font-weight:800;
  border:none;
  cursor:pointer;
  transition:all 0.25s cubic-bezier(0.4,0,0.2,1);
  text-decoration:none;
  font-family:var(--font);
  letter-spacing:0.02em;
  user-select:none;
  position:relative;
  overflow:hidden;
}
.btn::after{
  content:'';
  position:absolute;
  inset:0;
  background:linear-gradient(180deg,rgba(255,255,255,0.22) 0%,transparent 60%);
  border-radius:50px;
  pointer-events:none;
}
.btn:active{transform:scale(0.94)}
.btn:hover{transform:translateY(-3px)}

.btn-blue{
  background:linear-gradient(135deg,#4C97FF,#3D7FEC);
  color:white;
  box-shadow:0 8px 24px rgba(76,151,255,0.35);
}
.btn-blue:hover{box-shadow:0 12px 32px rgba(76,151,255,0.5)}

.btn-yellow{
  background:linear-gradient(135deg,#FFB830,#F59E0B);
  color:white;
  box-shadow:0 8px 24px rgba(255,184,48,0.35);
}
.btn-yellow:hover{box-shadow:0 12px 32px rgba(255,184,48,0.5)}

.btn-green{
  background:linear-gradient(135deg,#4ECB71,#35A052);
  color:white;
  box-shadow:0 8px 24px rgba(78,203,113,0.3);
}
.btn-green:hover{box-shadow:0 12px 32px rgba(78,203,113,0.45)}

.btn-purple{
  background:linear-gradient(135deg,#8559E6,#6A3FD0);
  color:white;
  box-shadow:0 8px 24px rgba(133,89,230,0.3);
}
.btn-purple:hover{box-shadow:0 12px 32px rgba(133,89,230,0.45)}

.btn-pink{
  background:linear-gradient(135deg,#FF6B9D,#E8557F);
  color:white;
  box-shadow:0 8px 24px rgba(255,107,157,0.3);
}
.btn-pink:hover{box-shadow:0 12px 32px rgba(255,107,157,0.45)}

.btn-outline{
  background:white;
  color:var(--blue);
  border:2.5px solid var(--blue);
}
.btn-outline:hover{
  background:var(--blue);
  color:white;
}

.btn-lg{padding:18px 42px;font-size:1.15rem;border-radius:60px}
.btn-sm{padding:8px 18px;font-size:0.86rem}
.btn-block{display:flex;width:100%}
.btn:disabled{opacity:0.5;pointer-events:none;filter:grayscale(0.3)}

/* ============ 首页专属 ============ */
.home-layout{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:32px;
  align-items:center;
  min-height:75vh;
  padding:20px 0;
}
.home-left{
  display:flex;
  flex-direction:column;
  gap:18px;
}
.home-title{
  font-size:2.8rem;
  font-weight:900;
  color:white;
  text-shadow:0 4px 20px rgba(0,0,0,0.15),0 2px 8px rgba(0,0,0,0.1);
  line-height:1.2;
  letter-spacing:0.04em;
}
.home-subtitle{
  font-size:1.1rem;
  color:rgba(255,255,255,0.92);
  text-shadow:0 2px 8px rgba(0,0,0,0.08);
  line-height:1.6;
  margin-bottom:4px;
}
/* ============ V3 首页全新设计 ============ */

/* 英雄区 — 居中对称 */
.hero-v3{
  text-align:center;
  padding:30px 20px 10px;
}
.hero-mascot-wrap{
  position:relative;
  display:inline-block;
  margin-bottom:16px;
}
.mascot-v3{
  position:relative;
  display:inline-block;
  animation:mascotFloatV3 3.5s ease-in-out infinite;
}
.mascot-body{
  font-size:5.5rem;
  display:inline-block;
  filter:drop-shadow(0 8px 20px rgba(0,0,0,0.12));
}
.mascot-hat{
  font-size:2.2rem;
  position:absolute;
  top:-18px;
  left:50%;
  transform:translateX(-50%) rotate(-15deg);
}
.mascot-glass{
  font-size:1.8rem;
  position:absolute;
  top:28px;
  right:-10px;
  animation:mascotFloatV3 4s ease-in-out infinite;
}
.mascot-shadow{
  width:100px;
  height:14px;
  background:rgba(0,0,0,0.08);
  border-radius:50%;
  margin:4px auto 0;
}
@keyframes mascotFloatV3{
  0%,100%{transform:translateY(0)}
  40%{transform:translateY(-14px)}
  70%{transform:translateY(-5px)}
}
/* 主标题 */
.hero-title-v3{
  font-size:2.4rem;
  font-weight:900;
  color:white;
  text-shadow:0 4px 20px rgba(0,0,0,0.15),0 2px 6px rgba(0,0,0,0.08);
  letter-spacing:0.06em;
  margin-bottom:10px;
  line-height:1.3;
}
.hero-subtitle-v3{
  font-size:1.05rem;
  color:rgba(255,255,255,0.93);
  text-shadow:0 2px 8px rgba(0,0,0,0.06);
  line-height:1.7;
  max-width:500px;
  margin:0 auto;
}
.hero-stars{
  margin-top:12px;
  display:flex;
  justify-content:center;
  gap:8px;
  font-size:0.9rem;
  opacity:0.7;
}

/* 三大功能卡片 — 居中均匀排列 */
.feature-cards-v3{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:20px;
  max-width:900px;
  margin:28px auto 0;
  padding:0 8px;
}
.fc3-card{
  display:flex;
  flex-direction:column;
  align-items:center;
  text-align:center;
  padding:32px 18px 22px;
  border-radius:28px;
  text-decoration:none;
  color:white;
  font-weight:800;
  transition:all 0.35s cubic-bezier(0.4,0,0.2,1);
  box-shadow:0 10px 32px rgba(0,0,0,0.12);
  position:relative;
  overflow:hidden;
  border:2px solid rgba(255,255,255,0.22);
  animation:cardFloat 5s ease-in-out infinite;
}
.fc3-card:nth-child(2){animation-delay:-1.5s}
.fc3-card:nth-child(3){animation-delay:-3s}
.fc3-card::after{
  content:'';
  position:absolute;
  inset:0;
  background:linear-gradient(180deg,rgba(255,255,255,0.18) 0%,transparent 55%);
  pointer-events:none;
  border-radius:28px;
}
.fc3-card:hover{
  transform:translateY(-10px) scale(1.04);
  box-shadow:0 20px 52px rgba(0,0,0,0.2);
}
.fc3-card:active{transform:scale(0.96)}
@keyframes cardFloat{
  0%,100%{transform:translateY(0)}
  50%{transform:translateY(-7px)}
}
/* 卡片颜色 */
.fc3-game{
  background:linear-gradient(160deg,#FF8C1A 0%,#FFB347 40%,#FF6680 100%);
}
.fc3-ai{
  background:linear-gradient(160deg,#667eea 0%,#8B7CF0 40%,#764ba2 100%);
}
.fc3-growth{
  background:linear-gradient(160deg,#11998e 0%,#38C07A 40%,#38ef7d 100%);
}
.fc3-icon{
  font-size:2.8rem;
  margin-bottom:10px;
  filter:drop-shadow(0 4px 8px rgba(0,0,0,0.1));
  transition:transform 0.3s;
}
.fc3-card:hover .fc3-icon{transform:scale(1.18)}
.fc3-title{
  font-size:1.15rem;
  font-weight:900;
  margin-bottom:10px;
  text-shadow:0 1px 3px rgba(0,0,0,0.08);
}
.fc3-desc{
  font-size:0.82rem;
  font-weight:600;
  opacity:0.92;
  line-height:1.65;
  margin-bottom:14px;
}
.fc3-arrow{
  font-size:0.82rem;
  font-weight:700;
  opacity:0.85;
  background:rgba(255,255,255,0.18);
  padding:6px 18px;
  border-radius:20px;
  border:1px solid rgba(255,255,255,0.25);
  transition:all 0.25s;
}
.fc3-card:hover .fc3-arrow{
  background:rgba(255,255,255,0.28);
  transform:scale(1.06);
}

/* 底部吉祥物 */
.bottom-mascot{
  text-align:center;
  padding:16px 0 4px;
  opacity:0.7;
}
.bottom-detective{
  font-size:2.5rem;
  animation:mascotFloatV3 4s ease-in-out infinite;
}
.bottom-detective span:nth-child(2){
  font-size:1.3rem;
  position:relative;
  top:-14px;
  left:-4px;
}
.bottom-tagline{
  font-size:0.9rem;
  color:rgba(255,255,255,0.85);
  font-weight:700;
  text-shadow:0 2px 6px rgba(0,0,0,0.06);
  margin-top:4px;
}

/* 响应式 — V3首页 */
@media (max-width:768px){
  .feature-cards-v3{grid-template-columns:1fr;max-width:380px}
  .hero-title-v3{font-size:1.7rem}
  .hero-subtitle-v3{font-size:0.92rem}
  .mascot-body{font-size:4rem}
  .fc3-card{padding:24px 16px 18px}
}
@media (max-width:420px){
  .hero-title-v3{font-size:1.4rem}
  .hero-subtitle-v3{font-size:0.84rem}
  .mascot-body{font-size:3.2rem}
}

/* ============ V3首页样式结束 ============ */

/* 四张功能大卡片 (保留旧版兼容) */
.feature-cards-grid{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:14px;
}
.feature-card-big{
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:24px 16px;
  border-radius:var(--radius-xl);
  text-decoration:none;
  color:white;
  font-weight:800;
  font-size:1.05rem;
  cursor:pointer;
  transition:all 0.35s cubic-bezier(0.4,0,0.2,1);
  box-shadow:0 8px 28px rgba(0,0,0,0.15);
  position:relative;
  overflow:hidden;
  border:2px solid rgba(255,255,255,0.25);
}
.feature-card-big::after{
  content:'';
  position:absolute;
  inset:0;
  background:linear-gradient(180deg,rgba(255,255,255,0.2) 0%,transparent 60%);
  pointer-events:none;
}
.feature-card-big:hover{
  transform:translateY(-6px) scale(1.03);
  box-shadow:0 16px 44px rgba(0,0,0,0.22);
}
.feature-card-big .fc-icon{font-size:2.2rem}
.feature-card-big .fc-label{font-size:1.05rem}
.feature-card-big .fc-desc{font-size:0.78rem;opacity:0.85;font-weight:600}
.fc-ai{background:linear-gradient(135deg,#667eea,#764ba2)}
.fc-knowledge{background:linear-gradient(135deg,#11998e,#38ef7d)}
.fc-bug{background:linear-gradient(135deg,#f093fb,#f5576c)}
.fc-growth{background:linear-gradient(135deg,#4facfe,#00f2fe)}

/* 右侧吉祥物区 */
.home-right{
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  position:relative;
  min-height:400px;
}
.mascot-platform{
  position:relative;
  display:flex;
  flex-direction:column;
  align-items:center;
}
.mascot-cloud{
  width:200px;
  height:70px;
  background:white;
  border-radius:70px;
  position:relative;
  box-shadow:0 12px 40px rgba(0,0,0,0.08);
  animation:mascotFloat 4s ease-in-out infinite;
}
.mascot-cloud::before{
  content:'';
  position:absolute;
  width:90px;height:90px;
  background:white;
  border-radius:50%;
  top:-45px;left:25px;
}
.mascot-cloud::after{
  content:'';
  position:absolute;
  width:110px;height:80px;
  background:white;
  border-radius:50%;
  top:-35px;left:70px;
}
.mascot-cat{
  font-size:6rem;
  position:absolute;
  top:-130px;
  left:50%;
  transform:translateX(-50%);
  animation:mascotFloat 4s ease-in-out infinite;
  filter:drop-shadow(0 12px 24px rgba(0,0,0,0.12));
  z-index:2;
}
.floating-items{
  position:absolute;
  inset:0;
  pointer-events:none;
}
.float-item{
  position:absolute;
  font-size:1.8rem;
  animation:floatAround 5s ease-in-out infinite;
  opacity:0.9;
  filter:drop-shadow(0 4px 8px rgba(0,0,0,0.08));
}
.float-item:nth-child(1){top:15%;left:5%;animation-delay:0s;font-size:2rem}
.float-item:nth-child(2){top:10%;right:10%;animation-delay:-1s;font-size:1.6rem}
.float-item:nth-child(3){top:40%;right:5%;animation-delay:-2s;font-size:2.2rem}
.float-item:nth-child(4){bottom:20%;left:8%;animation-delay:-3s;font-size:1.8rem}
.float-item:nth-child(5){bottom:30%;right:12%;animation-delay:-1.5s;font-size:1.5rem}
.float-item:nth-child(6){top:50%;left:15%;animation-delay:-2.5s;font-size:2rem}
@keyframes mascotFloat{
  0%,100%{transform:translateY(0)}
  50%{transform:translateY(-12px)}
}
@keyframes floatAround{
  0%,100%{transform:translateY(0) rotate(0deg)}
  30%{transform:translateY(-20px) rotate(5deg)}
  60%{transform:translateY(-8px) rotate(-3deg)}
}

/* ============ 闯关页 - 关卡地图 ============ */
.level-map{
  display:flex;
  flex-direction:column;
  gap:8px;
}
.level-node{
  display:flex;
  align-items:center;
  gap:12px;
  padding:12px 16px;
  border-radius:var(--radius-sm);
  background:rgba(255,255,255,0.7);
  cursor:pointer;
  transition:var(--transition);
  border:2px solid transparent;
  position:relative;
}
.level-node:hover{
  background:white;
  transform:translateX(4px);
  box-shadow:var(--shadow);
}
.level-node.completed{
  border-color:var(--green);
  background:rgba(78,203,113,0.12);
}
.level-node.current{
  border-color:var(--blue);
  background:rgba(76,151,255,0.1);
  box-shadow:0 0 0 4px rgba(76,151,255,0.15);
  animation:nodePulse 2s ease-in-out infinite;
}
.level-node.locked{
  opacity:0.5;
  cursor:not-allowed;
}
@keyframes nodePulse{
  0%,100%{box-shadow:0 0 0 4px rgba(76,151,255,0.15)}
  50%{box-shadow:0 0 0 12px rgba(76,151,255,0)}
}
.level-node-icon{
  width:38px;height:38px;
  border-radius:50%;
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:1.1rem;
  font-weight:900;
  flex-shrink:0;
}
.level-node.completed .level-node-icon{
  background:linear-gradient(135deg,#FFD700,#FFA500);
  box-shadow:0 4px 12px rgba(255,215,0,0.4);
}
.level-node:not(.completed):not(.locked) .level-node-icon{
  background:linear-gradient(135deg,#E8E8F0,#D0D0DC);
}
.level-node.locked .level-node-icon{
  background:#E0E0E8;
}
.level-node-info{flex:1}
.level-node-title{font-weight:800;font-size:0.88rem}
.level-node-topic{font-size:0.74rem;color:var(--text-light)}

/* ============ 闯关页 - 选项大按钮 ============ */
.answer-btn{
  display:block;
  width:100%;
  text-align:left;
  padding:18px 22px;
  margin-bottom:10px;
  border-radius:var(--radius);
  font-size:1rem;
  font-weight:700;
  cursor:pointer;
  transition:all 0.25s ease;
  font-family:var(--font);
  color:white;
  border:none;
  min-height:56px;
  position:relative;
  overflow:hidden;
}
.answer-btn::after{
  content:'';
  position:absolute;
  inset:0;
  background:linear-gradient(180deg,rgba(255,255,255,0.18) 0%,transparent 50%);
  pointer-events:none;
}
.answer-btn:hover{
  transform:translateX(6px) scale(1.02);
  box-shadow:0 8px 24px rgba(0,0,0,0.18);
}
.answer-btn:active{transform:scale(0.97)}
.ans-a{background:linear-gradient(135deg,#4ECB71,#35A052);box-shadow:0 6px 20px rgba(78,203,113,0.3)}
.ans-b{background:linear-gradient(135deg,#4C97FF,#3373CC);box-shadow:0 6px 20px rgba(76,151,255,0.3)}
.ans-c{background:linear-gradient(135deg,#FFB830,#E5A000);box-shadow:0 6px 20px rgba(255,184,48,0.3)}
.ans-d{background:linear-gradient(135deg,#8559E6,#6A3FD0);box-shadow:0 6px 20px rgba(133,89,230,0.3)}
.answer-btn:disabled{opacity:0.7;pointer-events:none}
.answer-btn.correct{
  animation:popCorrect 0.6s cubic-bezier(0.175,0.885,0.32,1.275);
  box-shadow:0 0 0 5px rgba(78,203,113,0.4),0 8px 24px rgba(78,203,113,0.4) !important;
}
.answer-btn.wrong{
  animation:shake 0.5s ease;
  opacity:0.65;
}
@keyframes popCorrect{
  0%{transform:scale(1)}
  40%{transform:scale(1.06)}
  100%{transform:scale(1)}
}
@keyframes shake{
  0%,100%{transform:translateX(0)}
  20%{transform:translateX(-10px)}
  40%{transform:translateX(10px)}
  60%{transform:translateX(-7px)}
  80%{transform:translateX(5px)}
}

/* ============ Scratch积木展示 ============ */
.blocks-area{
  display:flex;
  flex-direction:column;
  align-items:flex-start;
  gap:3px;
  padding:10px 0;
  font-family:'Courier New','PingFang SC',monospace;
}
.block-item{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:9px 16px;
  border-radius:8px;
  font-size:0.84rem;
  font-weight:700;
  color:white;
  min-width:40px;
  box-shadow:0 3px 0 rgba(0,0,0,0.2),inset 0 1px 0 rgba(255,255,255,0.22);
  transition:var(--transition);
  white-space:nowrap;
}
.block-item.indent{margin-left:26px}
.block-item.hat{border-radius:20px 20px 8px 8px}
.block-item.c-wrap{border-radius:14px 8px 8px 14px}
.block-item.label-block{
  background:transparent;
  color:var(--text-light);
  box-shadow:none;
  padding:6px 2px;
  font-weight:700;
  font-size:0.8rem;
  font-family:var(--font);
}
.block-inner{
  display:flex;
  flex-direction:column;
  gap:2px;
  margin-top:2px;
  padding-left:22px;
  border-left:3px dashed rgba(255,255,255,0.35);
}

/* ============ 反馈区 ============ */
.feedback{
  padding:16px 20px;
  border-radius:var(--radius);
  font-weight:700;
  font-size:0.95rem;
  display:none;
  align-items:center;
  gap:10px;
  margin-top:14px;
  animation:fadeInUp 0.4s ease;
}
.feedback.show{display:flex;flex-wrap:wrap}
.feedback.success{
  background:linear-gradient(135deg,#E0FFE8,#F0FFF5);
  color:#1D6B3A;
  border:2px solid var(--green);
}
.feedback.error{
  background:linear-gradient(135deg,#FFF5F5,#FFF0F0);
  color:#C03040;
  border:2px solid var(--red-light);
}
.feedback .exp-badge{
  margin-left:auto;
  background:linear-gradient(135deg,#FFD700,#FFA500);
  color:#5C3D00;
  padding:6px 16px;
  border-radius:20px;
  font-weight:900;
  font-size:0.9rem;
  animation:bounceIn 0.6s cubic-bezier(0.175,0.885,0.32,1.275);
  box-shadow:0 4px 14px rgba(255,215,0,0.4);
}
.hint-box{
  display:none;
  margin-top:12px;
  padding:16px 18px;
  background:linear-gradient(135deg,#FFF9E6,#FFF5D0);
  border-radius:var(--radius);
  font-size:0.9rem;
  line-height:1.6;
  border:2px dashed #FFD700;
}
.hint-box.show{display:block;animation:fadeInUp 0.4s ease}
.knowledge-box{
  display:none;
  margin-top:12px;
  padding:16px 18px;
  background:linear-gradient(135deg,#F0F6FF,#E0ECFF);
  border-radius:var(--radius);
  font-size:0.9rem;
  line-height:1.6;
  border-left:4px solid var(--blue);
}
.knowledge-box.show{display:block;animation:fadeInUp 0.4s ease}
@keyframes fadeInUp{
  from{opacity:0;transform:translateY(12px)}
  to{opacity:1;transform:translateY(0)}
}
@keyframes bounceIn{
  0%{transform:scale(0)}
  50%{transform:scale(1.25)}
  100%{transform:scale(1)}
}

/* ============ AI老师页面 ============ */
.ai-layout{
  display:grid;
  grid-template-columns:260px 1fr;
  gap:20px;
}
.ai-sidebar{
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:10px;
}
.ai-avatar-card{
  background:var(--card-bg);
  backdrop-filter:blur(10px);
  border-radius:var(--radius-xl);
  padding:24px 18px;
  text-align:center;
  box-shadow:var(--shadow);
  border:1px solid var(--glass-border);
  width:100%;
}
.ai-avatar-img{
  font-size:4.5rem;
  animation:mascotFloat 3s ease-in-out infinite;
  filter:drop-shadow(0 8px 16px rgba(0,0,0,0.1));
}
.ai-status{
  display:inline-flex;
  align-items:center;
  gap:5px;
  background:#E8F8E8;
  color:#2D7A2D;
  padding:4px 14px;
  border-radius:20px;
  font-weight:700;
  font-size:0.8rem;
  margin-top:6px;
}
.ai-stats-card{
  background:var(--card-bg);
  backdrop-filter:blur(10px);
  border-radius:var(--radius-lg);
  padding:18px;
  width:100%;
  box-shadow:var(--shadow);
  border:1px solid var(--glass-border);
}
.ai-stat-row{
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding:8px 0;
  border-bottom:1px solid #F0F0F5;
}
.ai-stat-row:last-child{border-bottom:none}
.ai-stat-label{font-size:0.82rem;color:var(--text-light);font-weight:600}
.ai-stat-value{font-size:1.1rem;font-weight:900;color:var(--blue)}
/* 聊天区 */
.chat-container{
  display:flex;
  flex-direction:column;
  height:500px;
  border-radius:var(--radius-xl);
  overflow:hidden;
  box-shadow:var(--shadow);
  background:white;
  border:1px solid var(--glass-border);
}
.chat-header{
  padding:12px 18px;
  background:linear-gradient(135deg,#F8FAFF,white);
  border-bottom:1px solid #F0F0F5;
  display:flex;
  align-items:center;
  gap:8px;
  font-weight:700;
  font-size:0.88rem;
}
.chat-messages{
  flex:1;
  overflow-y:auto;
  padding:16px;
  display:flex;
  flex-direction:column;
  gap:10px;
  background:linear-gradient(180deg,#F8FAFF,#F5F7FB);
}
.chat-msg{
  max-width:82%;
  padding:12px 16px;
  border-radius:18px;
  font-size:0.9rem;
  line-height:1.55;
  animation:fadeInUp 0.3s ease;
}
.chat-msg.ai{
  align-self:flex-start;
  background:white;
  border-bottom-left-radius:6px;
  box-shadow:0 2px 8px rgba(0,0,0,0.04);
  border:1px solid #EEF0F8;
}
.chat-msg.user{
  align-self:flex-end;
  background:linear-gradient(135deg,#4C97FF,#3D7FEC);
  color:white;
  border-bottom-right-radius:6px;
}
.chat-msg .msg-label{
  font-size:0.72rem;
  font-weight:700;
  margin-bottom:3px;
  opacity:0.7;
}
.chat-input-area{
  display:flex;
  gap:8px;
  padding:12px 16px;
  border-top:1px solid #EEE;
  background:white;
}
.chat-input-area input{
  flex:1;
  padding:12px 16px;
  border-radius:50px;
  border:2.5px solid #E4E6F0;
  font-size:0.92rem;
  font-family:var(--font);
  outline:none;
  transition:var(--transition);
}
.chat-input-area input:focus{
  border-color:var(--blue);
  box-shadow:0 0 0 4px rgba(76,151,255,0.08);
}
.chat-quick-btns{
  display:flex;
  gap:8px;
  padding:8px 16px 12px;
  flex-wrap:wrap;
}
.chat-quick-btn{
  padding:7px 16px;
  border-radius:20px;
  border:2px solid #E4E6F0;
  background:white;
  font-size:0.82rem;
  font-weight:700;
  cursor:pointer;
  transition:var(--transition);
  font-family:var(--font);
  white-space:nowrap;
}
.chat-quick-btn:hover{
  border-color:var(--blue);
  background:#F0F6FF;
  transform:translateY(-2px);
}
.chat-context{
  margin:0 16px;
  padding:10px 16px;
  background:linear-gradient(135deg,#FFF9E6,#FFF5D0);
  border-radius:var(--radius-sm);
  font-size:0.83rem;
  color:#8A6D14;
  border:1.5px dashed #FFD700;
}

/* ============ 成长中心 ============ */
.profile-header{
  text-align:center;
  padding:20px 0;
}
.profile-avatar{
  font-size:5rem;
  animation:mascotFloat 3.5s ease-in-out infinite;
  filter:drop-shadow(0 8px 16px rgba(0,0,0,0.1));
}
.profile-name{
  font-size:1.6rem;
  font-weight:900;
}
.profile-level{
  display:inline-block;
  background:linear-gradient(135deg,#4C97FF,#8559E6);
  color:white;
  padding:6px 22px;
  border-radius:20px;
  font-weight:800;
  font-size:0.9rem;
  margin-top:6px;
  box-shadow:0 4px 14px rgba(76,151,255,0.3);
}
.exp-bar-wrap{
  background:#E8E8F0;
  border-radius:14px;
  height:20px;
  margin-top:14px;
  overflow:hidden;
  max-width:460px;
  margin-left:auto;
  margin-right:auto;
  box-shadow:inset 0 2px 6px rgba(0,0,0,0.08);
}
.exp-bar-fill{
  height:100%;
  background:linear-gradient(90deg,#4C97FF,#7B8FFF,#8559E6,#FF6B9D);
  border-radius:14px;
  transition:width 1s cubic-bezier(0.4,0,0.2,1);
  position:relative;
}
.exp-bar-fill::after{
  content:'';
  position:absolute;
  top:4px;left:8px;right:8px;
  height:5px;
  background:rgba(255,255,255,0.35);
  border-radius:4px;
}
.stats-row{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(130px,1fr));
  gap:12px;
  margin:18px 0;
}
.stat-card{
  text-align:center;
  padding:22px 10px;
  background:var(--card-bg);
  backdrop-filter:blur(10px);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  transition:var(--transition);
  border:1px solid var(--glass-border);
}
.stat-card:hover{
  transform:translateY(-3px);
  box-shadow:var(--shadow-lg);
}
.stat-value{
  font-size:2rem;
  font-weight:900;
  background:linear-gradient(135deg,#4C97FF,#8559E6);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}
.stat-label{font-size:0.83rem;color:var(--text-light);margin-top:3px;font-weight:600}

/* 徽章墙 */
.badge-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(95px,1fr));
  gap:12px;
  margin-top:14px;
}
.badge-item{
  text-align:center;
  padding:16px 6px;
  background:var(--card-bg);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  transition:var(--transition);
  position:relative;
  overflow:hidden;
  border:1px solid var(--glass-border);
}
.badge-item.earned{
  border:2.5px solid #FFD700;
  background:linear-gradient(180deg,#FFFEF5,white);
}
.badge-item.earned::after{
  content:'✨';
  position:absolute;
  top:4px;right:6px;
  font-size:0.7rem;
  animation:sparkle 1.5s ease-in-out infinite;
}
.badge-item.locked{opacity:0.4;filter:grayscale(1)}
.badge-item:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.badge-icon{font-size:2.2rem;margin-bottom:5px}
.badge-name{font-size:0.76rem;font-weight:700;color:var(--text);line-height:1.2}
@keyframes sparkle{
  0%,100%{opacity:0.3;transform:scale(0.8)}
  50%{opacity:1;transform:scale(1.3)}
}

/* 章节网格 */
.chapter-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(170px,1fr));
  gap:12px;
  margin-top:14px;
}
.chapter-badge{
  display:flex;
  align-items:center;
  gap:10px;
  padding:14px 16px;
  background:var(--card-bg);
  backdrop-filter:blur(10px);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  transition:var(--transition);
  border:2px solid transparent;
}
.chapter-badge.completed{
  border-color:var(--green);
  background:linear-gradient(135deg,#F0FFF0,white);
}
.chapter-badge:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.chapter-icon{font-size:1.6rem}
.chapter-info{flex:1}
.chapter-name{font-weight:800;font-size:0.88rem}
.chapter-progress{font-size:0.73rem;color:var(--text-light);margin-top:2px}

/* ============ AI模式选择卡片 ============ */
.ai-mode-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:16px;
  margin:4px 0 16px;
}
.ai-mode-card{
  background:var(--card-bg);
  backdrop-filter:blur(10px);
  border-radius:var(--radius-xl);
  padding:26px 20px;
  text-align:center;
  box-shadow:var(--shadow);
  transition:all 0.3s cubic-bezier(0.4,0,0.2,1);
  border:2.5px solid transparent;
  cursor:pointer;
  position:relative;
  overflow:hidden;
}
.ai-mode-card:hover{
  transform:translateY(-6px);
  box-shadow:var(--shadow-lg);
}
.ai-mode-card:nth-child(1):hover{border-color:rgba(102,126,234,0.4);background:linear-gradient(180deg,rgba(102,126,234,0.06),white)}
.ai-mode-card:nth-child(2):hover{border-color:rgba(245,87,108,0.4);background:linear-gradient(180deg,rgba(245,87,108,0.06),white)}
.ai-mode-card:nth-child(3):hover{border-color:rgba(78,203,113,0.4);background:linear-gradient(180deg,rgba(78,203,113,0.06),white)}
.ai-mode-card:nth-child(4):hover{border-color:rgba(255,184,48,0.4);background:linear-gradient(180deg,rgba(255,184,48,0.06),white)}
.ai-mode-icon{font-size:2.8rem;margin-bottom:10px;transition:transform 0.3s}
.ai-mode-card:hover .ai-mode-icon{transform:scale(1.15)}
.ai-mode-title{font-weight:900;font-size:1.05rem;margin-bottom:6px}
.ai-mode-desc{font-size:0.84rem;color:var(--text-light);margin-bottom:8px;line-height:1.45}
.ai-mode-example{font-size:0.76rem;color:var(--blue);background:rgba(76,151,255,0.06);padding:6px 14px;border-radius:20px;display:inline-block}

/* ============ 上传区域 ============ */
.upload-area{
  display:block;
  border:3px dashed #D0D4E8;
  border-radius:var(--radius-xl);
  padding:36px 20px;
  cursor:pointer;
  transition:all 0.3s;
  margin:0 auto;
  max-width:400px;
}
.upload-area:hover{
  border-color:var(--blue);
  background:rgba(76,151,255,0.03);
}

/* ============ 知识问答卡片 ============ */
.quiz-list{display:flex;flex-direction:column;gap:12px;text-align:left;max-width:600px;margin:0 auto}
.quiz-card{
  background:var(--card-bg);
  border-radius:var(--radius);
  padding:18px 20px;
  box-shadow:var(--shadow);
  border:1.5px solid var(--glass-border);
  transition:all 0.3s;
}
.quiz-card:hover{transform:translateX(4px);box-shadow:var(--shadow-lg);border-color:rgba(76,151,255,0.2)}

/* ============ Toast / 弹窗 ============ */
.encourage-toast{
  position:fixed;
  top:24px;
  left:50%;
  transform:translateX(-50%);
  background:white;
  padding:14px 28px;
  border-radius:60px;
  box-shadow:0 12px 40px rgba(0,0,0,0.18);
  font-weight:800;
  font-size:1rem;
  z-index:200;
  animation:toastInOut 2.8s ease forwards;
  pointer-events:none;
  white-space:nowrap;
}
@keyframes toastInOut{
  0%{opacity:0;transform:translateX(-50%) translateY(-24px)}
  12%{opacity:1;transform:translateX(-50%) translateY(0)}
  82%{opacity:1;transform:translateX(-50%) translateY(0)}
  100%{opacity:0;transform:translateX(-50%) translateY(-24px)}
}
.achievement-modal{
  position:fixed;
  inset:0;
  background:rgba(0,0,0,0.45);
  display:flex;
  align-items:center;
  justify-content:center;
  z-index:300;
  animation:fadeIn 0.3s ease;
}
.achievement-card{
  background:white;
  border-radius:var(--radius-xl);
  padding:36px 32px;
  text-align:center;
  max-width:380px;
  box-shadow:0 24px 72px rgba(0,0,0,0.25);
  animation:popIn 0.55s cubic-bezier(0.175,0.885,0.32,1.275);
}
.achievement-icon{font-size:4rem;margin-bottom:8px}
.achievement-title{font-size:1.4rem;font-weight:900;margin-bottom:6px}
.achievement-desc{font-size:0.9rem;color:var(--text-light);margin-bottom:18px}
@keyframes popIn{
  0%{transform:scale(0.4);opacity:0}
  100%{transform:scale(1);opacity:1}
}
@keyframes fadeIn{from{opacity:0}to{opacity:1}}

/* ============ 章节封面卡片 ============ */
.chapter-cover{
  text-align:center;
  padding:32px 20px;
  background:linear-gradient(135deg,rgba(255,255,255,0.95),rgba(255,255,255,0.8));
  backdrop-filter:blur(12px);
  border-radius:var(--radius-xl);
  box-shadow:var(--shadow-lg);
  border:2px solid rgba(255,255,255,0.6);
  margin-bottom:20px;
}
.chapter-cover-icon{font-size:4rem;margin-bottom:12px;animation:mascotFloat 3s ease-in-out infinite}
.chapter-cover-title{font-size:1.6rem;font-weight:900;margin-bottom:6px}
.chapter-cover-desc{font-size:0.95rem;color:var(--text-light);margin-bottom:4px}
.chapter-cover-badge{display:inline-block;background:linear-gradient(135deg,#FFD700,#FFA500);color:white;padding:6px 20px;border-radius:20px;font-weight:800;font-size:0.88rem;box-shadow:0 4px 14px rgba(255,215,0,0.35);}

/* ============ 彩带粒子 ============ */
.confetti-piece{
  position:fixed;
  pointer-events:none;
  z-index:400;
  animation:confettiFall 2.5s ease-out forwards;
}
@keyframes confettiFall{
  0%{transform:translateY(-100px) rotate(0deg) scale(1);opacity:1}
  100%{transform:translateY(110vh) rotate(720deg) scale(0.3);opacity:0}
}

/* ============ 页脚 ============ */
.footer{
  text-align:center;
  padding:16px;
  color:var(--text-light);
  font-size:0.83rem;
}

/* ============ 响应式 ============ */
@media (max-width:860px){
  .home-layout{
    grid-template-columns:1fr;
    min-height:auto;
    gap:20px;
  }
  .home-title{font-size:2rem}
  .feature-cards-grid{grid-template-columns:1fr 1fr}
  .ai-layout{grid-template-columns:1fr}
  .ai-sidebar{flex-direction:row;flex-wrap:wrap;justify-content:center}
  .ai-avatar-card,.ai-stats-card{width:auto;min-width:180px}
}
@media (max-width:600px){
  .home-title{font-size:1.5rem}
  .home-subtitle{font-size:0.9rem}
  .feature-cards-grid{grid-template-columns:1fr}
  .navbar{padding:8px 12px}
  .nav-links a{padding:8px 12px;font-size:0.8rem}
  .nav-logo{font-size:1.05rem}
  .mascot-cat{font-size:3.5rem;top:-70px}
  .mascot-cloud{width:130px;height:45px}
  .container{padding:12px 10px 40px}
  .btn-lg{padding:14px 28px;font-size:1rem}
  .answer-btn{padding:14px 18px;font-size:0.9rem;min-height:50px}
  .chat-container{height:380px}
  .badge-grid{grid-template-columns:repeat(3,1fr)}
  .chapter-grid{grid-template-columns:1fr 1fr}
}