*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:'Poppins',sans-serif;
}

body{
    min-height:100vh;

    background:
    radial-gradient(
        circle at 50% 0%,
        rgba(63,169,245,.18),
        transparent 55%
    ),
    linear-gradient(
        135deg,
        #0A1E33 0%,
        #1A4C8B 55%,
        #3FA9F5 100%
    );

    color:white;
}

/* HERO */

.hero{

    background:
    radial-gradient(
        circle at 50% 0%,
        rgba(63,169,245,.18),
        transparent 55%
    ),
    linear-gradient(
        135deg,
        #0A1E33 0%,
        #1A4C8B 55%,
        #3FA9F5 100%
    );

    text-align:center;

    padding:90px 20px;
}

.hero h1{
    font-size:64px;
    margin-bottom:20px;
}

.hero p{
    color:#D8E1E8;
    font-size:20px;
    margin-bottom:45px;
}

.stats{
    display:flex;
    justify-content:center;
    gap:30px;
    flex-wrap:wrap;
}

.stat-card{

    width:200px;

    padding:30px;

    border-radius:18px;

    background:rgba(255,255,255,.08);

    backdrop-filter:blur(20px);

    border:1px solid rgba(255,255,255,.12);

    box-shadow:
    0 10px 40px rgba(0,0,0,.25);
}

.stat-card h2{
    font-size:48px;
    margin-bottom:10px;

    color:#00E5FF;
}

.stat-card span{
    color:#D8E1E8;
}

/* TOPIC SECTION */

.topics-section{

    background:transparent;

    padding:70px 0;
}

.topics{

    width:85%;

    margin:auto;

    display:grid;

    grid-template-columns:repeat(3,1fr);

    gap:30px;
}

/* CARD */

.topic-card{

    background:linear-gradient(
        145deg,
        #172537 0%,
        #11171F 100%
    );

    border:1px solid #243447;

    border-radius:20px;

    padding:25px;

    min-height:230px;

    cursor:pointer;

    transition:.3s;

    display:flex;

    flex-direction:column;

    box-shadow:
    0 20px 50px rgba(10,30,51,.35);
}

.topic-card:hover{

    transform:translateY(-6px);

    border-color:#3FA9F5;

    box-shadow:
    0 20px 60px rgba(63,169,245,.25);
}

.card-top{

    display:flex;

    justify-content:space-between;

    align-items:center;

    margin-bottom:25px;
}

.badge{

    padding:8px 16px;

    border-radius:999px;

    font-size:14px;

    font-weight:600;
}

.easy-badge{
    background:#A6E22E;
    color:#0A1E33;
}

.medium-badge{
    background:#00E5FF;
    color:#0A1E33;
}

.hard-badge{
    background:#EF4444;
    color:white;
}

.duration{
    color:#B8C4D4;
}

.topic-card h3{

    font-size:32px;

    margin-bottom:18px;

    color:#FFFFFF;
}

.topic-card p{

    color:#94A3B8;

    line-height:1.7;

    flex:1;
}

.card-footer{

    color:#B8C4D4;

    margin-top:25px;
}

@media(max-width:1200px){

    .topics{
        grid-template-columns:repeat(2,1fr);
    }
}

@media(max-width:768px){

    .hero h1{
        font-size:42px;
    }

    .topics{
        grid-template-columns:1fr;
    }
}