*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

body{
    min-height:100vh;
    display:flex;
    align-items:center;
    justify-content:center;
    background: radial-gradient(circle at top, #87ceeb, #0d1f33);
    transition: background 0.4s;
}

.age-container{
    background: linear-gradient(160deg, #1e90ff, #00bfff);
    padding:40px 45px;
    border-radius:28px;
    width:320px;
    text-align:center;
    box-shadow:0 20px 60px rgba(0,0,0,0.5);
    transition: transform 0.3s, box-shadow 0.3s;
}

.age-container:hover{
    transform: translateY(-6px);
    box-shadow:0 30px 80px rgba(0,0,0,0.6);
}

.mode-btns{
    display:flex;
    justify-content:center;
    gap:12px;
    margin-bottom:20px;
}

.mode-btns button{
    padding:6px 14px;
    border:none;
    border-radius:20px;
    cursor:pointer;
    font-size:13px;
    transition:0.3s;
}

.mode-btns button:hover{
    background:#1e90ff;
    color:#fff;
}

h2{
    color:#fff;
    margin-bottom:8px;
}

.format{
    color:#e0f6ff;
    font-size:12px;
    margin-bottom:18px;
}

input{
    width:100%;
    padding:14px;
    border:none;
    border-radius:25px;
    outline:none;
    font-size:14px;
    text-align:center;
    margin-bottom:22px;
    background: rgba(255,255,255,0.9);
    color:#0d1f33;
    transition: 0.3s;
}

input:focus{
    box-shadow: 0 0 0 2px rgba(30,144,255,0.4);
}

.dark input{
    background: rgba(255,255,255,0.1);
    color:#fff;
}


.calc-btn{
    width:100%;
    padding:14px;
    border:none;
    border-radius:30px;
    background:#00bfff;
    color:#fff;
    font-weight:600;
    letter-spacing:1px;
    cursor:pointer;
    box-shadow:0 10px 25px rgba(0,0,0,0.4);
    transition:0.3s;
}

.calc-btn:hover{
    background:#04ff26ea;
    transform: translateY(-4px) scale(1.05);
}

#result{
    margin-top:18px;
    font-weight:600;
    color:#00ff7f;
}

.dark{
    background: radial-gradient(circle at top, #020617, #000);
}

.dark .age-container{
    background: linear-gradient(160deg, #020617, #0b1220);
}

@media(max-width:400px){
    .age-container{
        width:90%;
        padding:35px 30px;
    }
}