body {
    margin: 0;
    font-family: 'Poppins', sans-serif;
    background: #020617;
    color: white;
}

/* NAV */
header {
    display: flex;
    justify-content: space-between;
    padding: 20px 50px;
}

/* HERO */
.hero {
    display: flex;
    padding: 60px;
    align-items: center;
    justify-content: space-between;
}

.hero img {
    width: 400px;
    border-radius: 20px;
}

/* BUTTON */
.btn {
    padding: 12px 25px;
    background: linear-gradient(45deg, #38bdf8, #6366f1);
    border: none;
    color: white;
    cursor: pointer;
    border-radius: 10px;
    transition: 0.3s;
}

.btn:hover {
    transform: scale(1.1);
}

/* DEMO CALCULATOR */
.demo {
    text-align: center;
    padding: 50px;
}

.calc-box {
    background: #0f172a;
    padding: 20px;
    width: 260px;
    margin: auto;
    border-radius: 15px;
    box-shadow: 0 0 20px rgba(56,189,248,0.5);
}

#display {
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    border: none;
    font-size: 18px;
}

.buttons button {
    width: 23%;
    margin: 2px;
    padding: 10px;
    border: none;
    background: #1e293b;
    color: white;
    cursor: pointer;
}

.buttons button:hover {
    background: #38bdf8;
}

/* FEATURES */
.feature-grid {
    display: flex;
    gap: 20px;
    padding: 30px;
}

.card {
    background: #0f172a;
    padding: 20px;
    border-radius: 15px;
    transition: 0.4s;
}

.card:hover {
    transform: translateY(-10px);
}

/* 🔥 ANIMATIONS */
.fade-up {
    animation: fadeUp 1s ease;
}

.fade-left {
    animation: fadeLeft 1s ease;
}

.fade-right {
    animation: fadeRight 1s ease;
}

.fade-down {
    animation: fadeDown 1s ease;
}

@keyframes fadeUp {
    from {opacity:0; transform: translateY(40px);}
    to {opacity:1; transform: translateY(0);}
}

@keyframes fadeLeft {
    from {opacity:0; transform: translateX(-40px);}
    to {opacity:1; transform: translateX(0);}
}

@keyframes fadeRight {
    from {opacity:0; transform: translateX(40px);}
    to {opacity:1; transform: translateX(0);}
}

@keyframes fadeDown {
    from {opacity:0; transform: translateY(-40px);}
    to {opacity:1; transform: translateY(0);}
}