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

body{
    font-family:Arial,sans-serif;
    background:#f1f5f9;
    padding:25px;
    color:#1e293b;
}

.container{
    width:100%;
    max-width:600px;
    margin:auto;
}

/* CARD */
.card{
    background:#fff;
    border-radius:18px;
    padding:25px;
    border:1px solid #dbe4ee;
    box-shadow:0 10px 25px rgba(0,0,0,0.05);
}

.card h2{
    font-size:24px;
    margin-bottom:18px;
    color:#0f172a;
}

/* INPUT */
.input-group{
    margin-bottom:18px;
}

.input-group label{
    display:block;
    margin-bottom:8px;
    font-weight:600;
}

.input-group input{
    width:100%;
    padding:14px;
    border-radius:12px;
    border:1px solid #cbd5e1;
    font-size:16px;
}

/* BUTTONS */
.button-group{
    display:flex;
    gap:12px;
}

button{
    padding:13px 22px;
    border:none;
    border-radius:12px;
    cursor:pointer;
    font-weight:600;
}

.calculate-btn{
    background:#2563eb;
    color:#fff;
}

.clear-btn{
    background:#f1f5f9;
    border:1px solid #cbd5e1;
}

/* RESULT */
.result-box{
    margin-top:20px;
    background:#dcfce7;
    padding:18px;
    border-radius:14px;
    display:none;
}

.result-value{
    font-size:26px;
    font-weight:700;
    color:#14532d;
}

/* ERROR */
.error-box{
    margin-top:15px;
    background:#fee2e2;
    color:#b91c1c;
    padding:14px;
    border-radius:12px;
    display:none;
}

/* STEPS */
.steps{
    margin-top:15px;
}

.steps-content{
    display:none;
    margin-top:10px;
    background:#f8fafc;
    padding:12px;
    border-radius:10px;
}