:root{
  --android-green:#3ddc84;
  --android-blue:#4285f4;
  --android-red:#ea4335;
  --android-yellow:#fbbc04;
  --teal-primary:#00897b;
  --teal-light:#4db6ac;
  --tech-dark:#202124;
  --tech-grey:#5f6368;
  --tech-light:#f8f9fa;
}

*{
  box-sizing:border-box;
  margin:0;
  padding:0;
}

body{
  font-family:'Roboto', system-ui, sans-serif;
  background:var(--tech-light);
  color:var(--tech-dark);
  line-height:1.75;
}

/* Mobile app header */
.mobile-header{
  background:linear-gradient(135deg, var(--teal-primary), var(--android-green));
  padding:80px 40px 120px;
  position:relative;
  overflow:hidden;
}

.phone-frame{
  position:absolute;
  right:10%;
  top:50%;
  transform:translateY(-50%);
  width:200px;
  height:400px;
  border:8px solid rgba(255,255,255,0.2);
  border-radius:30px;
  background:rgba(255,255,255,0.1);
  backdrop-filter:blur(10px);
}

.phone-frame::before{
  content:"";
  position:absolute;
  top:15px;
  left:50%;
  transform:translateX(-50%);
  width:60px;
  height:6px;
  background:rgba(255,255,255,0.3);
  border-radius:3px;
}

.header-inner{
  max-width:1000px;
  margin:auto;
  position:relative;
  z-index:1;
}

.android-badge{
  display:inline-flex;
  align-items:center;
  gap:10px;
  background:rgba(255,255,255,0.25);
  backdrop-filter:blur(10px);
  border:2px solid rgba(255,255,255,0.4);
  padding:10px 25px;
  border-radius:50px;
  color:#fff;
  font-weight:800;
  font-size:0.85rem;
  margin-bottom:25px;
  letter-spacing:2px;
  text-transform:uppercase;
}

.mobile-title{
  font-size:3.5rem;
  color:#fff;
  font-weight:900;
  margin-bottom:25px;
  line-height:1.2;
  max-width:700px;
}

.mobile-subtitle{
  font-size:1.25rem;
  color:rgba(255,255,255,0.95);
  max-width:650px;
  line-height:1.7;
}

/* Container */
.container{
  max-width:1100px;
  margin:0 auto;
  padding:0 40px;
}

/* Intro section */
.intro-section{
  background:#fff;
  border-radius:16px;
  padding:50px;
  margin:80px 0 40px;
  box-shadow:0 4px 20px rgba(0,0,0,0.08);
}

.intro-section h2{
  font-size:2rem;
  color:var(--tech-dark);
  margin-bottom:20px;
  font-weight:800;
}

.intro-section p{
  font-size:1.05rem;
  color:var(--tech-grey);
  line-height:1.9;
  margin-bottom:15px;
}

/* Step cards */
.steps-wrapper{
  margin:40px 0;
}

.step-card{
  background:#fff;
  border-radius:16px;
  padding:40px;
  margin-bottom:40px;
  box-shadow:0 4px 20px rgba(0,0,0,0.08);
  border-left:6px solid var(--teal-primary);
  display:flex;
  gap:30px;
  align-items:flex-start;
  transition:all 0.3s ease;
}

.step-card:hover{
  box-shadow:0 8px 30px rgba(0,0,0,0.12);
  transform:translateY(-4px);
}

.step-card:nth-child(1){
  border-left-color:#00897b;
}

.step-card:nth-child(2){
  border-left-color:#26a69a;
}

.step-card:nth-child(3){
  border-left-color:#4db6ac;
}

.step-card:nth-child(4){
  border-left-color:#00897b;
}

.step-card:nth-child(5){
  border-left-color:#26a69a;
}

.step-number{
  flex:0 0 80px;
  width:80px;
  height:80px;
  background:linear-gradient(135deg, var(--teal-primary), var(--android-green));
  border-radius:50%;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  color:#fff;
  font-weight:900;
  box-shadow:0 6px 20px rgba(0,137,123,0.3);
  flex-shrink:0;
}

.step-number .label{
  font-size:0.7rem;
  opacity:0.9;
}

.step-number .num{
  font-size:2rem;
  line-height:1;
}

.step-content h2{
  font-size:1.9rem;
  color:var(--tech-dark);
  margin-bottom:20px;
  font-weight:800;
}

.step-content p{
  font-size:1.05rem;
  color:var(--tech-grey);
  line-height:1.9;
  margin-bottom:15px;
}

.step-content ul{
  list-style:none;
  padding:0;
  margin:20px 0;
}

.step-content ul li{
  padding-left:30px;
  position:relative;
  font-size:1.05rem;
  color:var(--tech-grey);
  line-height:1.8;
  margin-bottom:10px;
}

.step-content ul li::before{
  content:"•";
  position:absolute;
  left:0;
  color:var(--teal-primary);
  font-weight:900;
  font-size:1.4rem;
}

/* Important box */
.important-box{
  background:linear-gradient(135deg, #e0f2f1, #b2dfdb);
  border:3px solid var(--teal-primary);
  border-radius:12px;
  padding:40px;
  margin:40px 0;
  position:relative;
}

.important-box::before{
  content:"⚠️";
  position:absolute;
  top:20px;
  left:20px;
  font-size:3rem;
}

.important-content{
  padding-left:80px;
}

.important-box h3{
  font-size:1.8rem;
  color:#00695c;
  margin-bottom:15px;
  font-weight:800;
}

.important-box p{
  font-size:1.05rem;
  color:#00695c;
  line-height:1.8;
}

.important-box .check-item{
  display:flex;
  align-items:center;
  gap:10px;
  margin:10px 0;
  font-size:1.05rem;
  color:#00695c;
}

/* Tips section */
.tips-section{
  background:#fff;
  border-radius:16px;
  padding:50px;
  margin:60px 0;
  box-shadow:0 4px 20px rgba(0,0,0,0.08);
}

.tips-section h2{
  font-size:2rem;
  color:var(--tech-dark);
  margin-bottom:30px;
  font-weight:800;
  text-align:center;
}

.tips-section ul{
  list-style:none;
  padding:0;
}

.tips-section ul li{
  padding-left:35px;
  position:relative;
  font-size:1.05rem;
  color:var(--tech-grey);
  line-height:1.8;
  margin-bottom:15px;
}

.tips-section ul li::before{
  content:"✓";
  position:absolute;
  left:0;
  color:var(--android-green);
  font-weight:900;
  font-size:1.3rem;
}

/* Recovery section */
.recovery-section{
  background:#fff;
  border-radius:16px;
  padding:50px;
  margin:40px 0;
  box-shadow:0 4px 20px rgba(0,0,0,0.08);
  border-top:5px solid var(--android-yellow);
}

.recovery-section h2{
  font-size:2rem;
  color:var(--tech-dark);
  margin-bottom:25px;
  font-weight:800;
}

.recovery-section p, .recovery-section ul li{
  font-size:1.05rem;
  color:var(--tech-grey);
  line-height:1.9;
}

.recovery-section ul{
  list-style:none;
  padding:0;
  margin:20px 0;
}

.recovery-section ul li{
  padding-left:30px;
  position:relative;
  margin-bottom:12px;
}

.recovery-section ul li::before{
  content:"→";
  position:absolute;
  left:0;
  color:var(--android-yellow);
  font-weight:900;
  font-size:1.2rem;
}

/* Link */
a{
  color:var(--android-blue);
  text-decoration:none;
  font-weight:700;
  border-bottom:2px solid var(--android-blue);
  transition:all 0.3s ease;
}

a:hover{
  color:var(--teal-primary);
  border-color:var(--teal-primary);
}

/* Conclusion */
.conclusion{
  background:linear-gradient(135deg, var(--teal-primary), var(--android-green));
  color:#fff;
  padding:60px 50px;
  border-radius:16px;
  text-align:center;
  margin:80px 0 60px;
  box-shadow:0 15px 50px rgba(0,137,123,0.3);
}

.conclusion h2{
  font-size:2.5rem;
  margin-bottom:20px;
  font-weight:900;
}

.conclusion p{
  font-size:1.15rem;
  line-height:1.9;
  max-width:850px;
  margin:auto;
  opacity:0.95;
}

/* Footer */
.footer{
  background:var(--tech-dark);
  color:#9aa0a6;
  text-align:center;
  padding:40px 20px;
  font-size:0.9rem;
}

/* Responsive */
@media(max-width:900px){
  .mobile-title{
    font-size:2.5rem;
  }
  
  .phone-frame{
    display:none;
  }
  
  .step-card{
    flex-direction:column;
    gap:20px;
  }
  
  .intro-section, .tips-section, .recovery-section{
    padding:30px;
  }
  
  .important-content{
    padding-left:0;
  }
  
  .important-box::before{
    position:static;
    display:block;
    margin-bottom:15px;
  }
}