@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600;700&display=swap');

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

body.light {
    background: linear-gradient(135deg, #4203a9, #90bafc);
}

body.dark {
    background: linear-gradient(135deg, #121212, #2c2c2c);
}

.container {
    width: 100%;
    min-height: 100vh;
    padding: 15px;
    color: #fff;
}

.calculator {
    max-width: 600px;
    margin: auto;
    margin-top: 100px;
}

.calculator h1 {
    font-size: 48px;
}

.calculator span {
    color: #ffff76;
}

.input-box {
    margin: 30px 0;
    padding: 25px;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.25);
    display: flex;
    gap: 10px;
}

.input-box input,
.input-box button {
    font-size: 16px;
    padding: 12px;
    border-radius: 5px;
    border: none;
    outline: none;
}

.input-box input {
    flex: 1;
}

.input-box button {
    background: #ffff76;
    cursor: pointer;
}

#result, #birthday {
    margin-top: 15px;
    font-size: 18px;
    color: #ffff76;
}

/* Dark / Light Button */
.theme-btn {
    position: fixed;
    top: 15px;
    right: 15px;
    background: #ffff76;
    color: #333;
    border: none;
    padding: 8px 15px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
}

/* 📱 Mobile Responsive */
@media (max-width: 600px) {
    .calculator h1 {
        font-size: 36px;
    }
    .input-box {
        flex-direction: column;
    }
}