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

html{
    scroll-behavior:smooth;
}

body{
    font-family:'Trebuchet MS', Arial, sans-serif;
    background:#f9fbff;
    color:#333;
}

/* HERO */

.hero{
    background:linear-gradient(135deg,#5ec8ff,#7b68ee);
    color:white;
    text-align:center;
    padding:80px 20px;
    border-bottom-left-radius:50px;
    border-bottom-right-radius:50px;
}

.logo{
    display:inline-block;
    background:white;
    color:#6a4cff;
    padding:10px 25px;
    border-radius:30px;
    font-size:28px;
    font-weight:bold;
    margin-bottom:25px;
}

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

.hero p{
    max-width:850px;
    margin:0 auto 30px auto;
    font-size:24px;
    line-height:1.6;
}

.hero-btn{
    display:inline-block;
    text-decoration:none;
    background:#ffca28;
    color:#4e342e;
    font-size:22px;
    font-weight:bold;
    padding:18px 35px;
    border-radius:40px;
    transition:.3s;
}

.hero-btn:hover{
    transform:translateY(-4px);
}

/* NAV */

.main-nav{
    position:sticky;
    top:0;
    z-index:1000;

    background:white;
    display:flex;
    justify-content:center;
    gap:30px;

    padding:18px;
    box-shadow:0 2px 15px rgba(0,0,0,.08);
}

.main-nav a{
    text-decoration:none;
    color:#6a4cff;
    font-size:18px;
    font-weight:bold;
}

/* SECTIONS */

.section{
    width:90%;
    max-width:1300px;
    margin:70px auto;
}

.section h2{
    text-align:center;
    font-size:42px;
    color:#5a36d6;
    margin-bottom:35px;
}

/* CARDS */

.cards{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(260px,1fr));
    gap:25px;
}

.card{
    background:white;
    text-decoration:none;
    color:#333;

    padding:30px;
    border-radius:30px;

    box-shadow:0 8px 20px rgba(0,0,0,.08);

    transition:.3s;
}

.card:hover{
    transform:translateY(-8px);
}

.card h3{
    font-size:28px;
    margin:15px 0;
    color:#5a36d6;
}

.card p{
    line-height:1.6;
}

.icon{
    font-size:60px;
}

.english-flag-icon{
    display:inline-block;
    width:1.45em;
    height:.9em;
    position:relative;
    vertical-align:-.08em;
    background:
        linear-gradient(32deg, transparent 0 41%, #fff 41% 48%, #c8102e 48% 53%, #fff 53% 60%, transparent 60%),
        linear-gradient(-32deg, transparent 0 41%, #fff 41% 48%, #c8102e 48% 53%, #fff 53% 60%, transparent 60%),
        linear-gradient(90deg, transparent 0 38%, #fff 38% 44%, #c8102e 44% 56%, #fff 56% 62%, transparent 62%),
        linear-gradient(0deg, transparent 0 34%, #fff 34% 42%, #c8102e 42% 58%, #fff 58% 66%, transparent 66%),
        #012169;
    border:2px solid #d8dde6;
    border-radius:6px;
    box-shadow:0 4px 10px rgba(0,0,0,.12);
    overflow:hidden;
}

.icon .english-flag-icon{
    font-size:54px;
}

.logo .english-flag-icon,
.quiz-header .english-flag-icon,
.start-emoji .english-flag-icon{
    font-size:1.25em;
    margin-right:8px;
}

.main-card{
    border:4px solid #ffca28;
}

/* SUBJECT CATEGORIES */

.category-list{
    background:white;
    border:1px solid #edf0f7;
    border-radius:24px;
    box-shadow:0 8px 20px rgba(0,0,0,.06);
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(180px,1fr));
    gap:18px 28px;
    padding:28px;
}

.category-item{
    display:flex;
    align-items:center;
    gap:10px;
    color:#111827;
    font-size:18px;
    font-weight:bold;
    min-height:54px;
    text-decoration:none;
    transition:.2s;
}

.category-item:hover{
    color:#5a36d6;
    transform:translateY(-2px);
}

.category-item span{
    line-height:1.3;
}

/* RAZREDI */

.grade-number{
    width:80px;
    height:80px;
    border-radius:50%;

    background:linear-gradient(135deg,#ffca28,#ff7043);

    display:flex;
    justify-content:center;
    align-items:center;

    font-size:40px;
    color:white;
    font-weight:bold;

    margin:0 auto 20px auto;
}

.grades .card{
    text-align:center;
}

.active{
    border:4px solid #4caf50;
}

.locked{
    opacity:.8;
}

/* START SECTION */

.start-section{
    text-align:center;
    background:white;
    padding:50px;
    border-radius:35px;
    box-shadow:0 8px 20px rgba(0,0,0,.08);
}

.start-section p{
    max-width:900px;
    margin:20px auto 35px auto;
    font-size:22px;
    line-height:1.8;
}

.big-btn{
    display:inline-block;

    text-decoration:none;

    background:linear-gradient(
        135deg,
        #42a5f5,
        #66bb6a
    );

    color:white;

    font-size:26px;
    font-weight:bold;

    padding:20px 45px;

    border-radius:50px;

    transition:.3s;
}

.big-btn:hover{
    transform:scale(1.05);
}

/* FOOTER */

footer{
    margin-top:80px;

    background:#5a36d6;

    color:white;

    text-align:center;

    padding:35px;

    border-top-left-radius:40px;
    border-top-right-radius:40px;
}

footer p{
    font-size:20px;
}

/* MOBILE */

@media(max-width:768px){

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

    .hero p{
        font-size:18px;
    }

    .main-nav{
        flex-wrap:wrap;
        gap:15px;
    }

    .section h2{
        font-size:32px;
    }

    .start-section{
        padding:30px;
    }

    .start-section p{
        font-size:18px;
    }

    .big-btn{
        font-size:20px;
        padding:15px 25px;
    }
}