body {
    margin: 0;
    min-height: 100vh;
    background: linear-gradient(120deg, #232526 60%, #414345 100%);
    font-family: 'Montserrat', Arial, sans-serif;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
}

.calc-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    width: 100vw;
}

.calc-3d {
    background: linear-gradient(135deg, #232526 60%, #485563 100%);
    border-radius: 24px;
    box-shadow: 0 12px 40px 0 rgba(0,0,0,0.45), 0 1.5px 0 #90caf9 inset;
    padding: 32px 24px 24px 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    transform: perspective(800px) rotateX(8deg) rotateY(-8deg);
    transition: box-shadow 0.3s;
    max-width: 370px;
    width: 100%;
}

.calc-display {
    width: 100%;
    min-height: 56px;
    background: rgba(255,255,255,0.09);
    border-radius: 12px;
    margin-bottom: 18px;
    font-size: 2.2rem;
    text-align: right;
    padding: 16px 18px;
    box-shadow: 0 2px 8px rgba(33,150,243,0.08) inset;
    color: #fff;
    letter-spacing: 1px;
    overflow-x: auto;
}

.calc-buttons, .calc-advanced {
    display: grid;
    gap: 12px;
    width: 100%;
}

.calc-buttons {
    grid-template-columns: repeat(4, 1fr);
    margin-bottom: 18px;
}

.calc-advanced {
    grid-template-columns: repeat(5, 1fr);
    margin-top: 8px;
}

.btn {
    background: linear-gradient(180deg, #222 60%, #333 100%);
    border: none;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(33,150,243,0.08);
    color: #fff;
    font-size: 1.1rem;
    font-weight: 700;
    padding: 16px 0;
    cursor: pointer;
    transition: background 0.2s, transform 0.15s;
    outline: none;
    user-select: none;
    -webkit-user-select: none; /* Soporte Safari/iOS */
}

.btn:active {
    background: linear-gradient(180deg, #1976d2 60%, #64b5f6 100%);
    color: #fff;
    transform: scale(0.97);
}

.btn.adv {
    background: linear-gradient(180deg, #263238 60%, #37474f 100%);
    font-size: 1rem;
    padding: 12px 0;
}

.btn[data-action="equals"] {
    background: linear-gradient(90deg, #1976d2 60%, #64b5f6 100%);
    color: #fff;
}

.btn[data-action="equals"]:active {
    background: linear-gradient(90deg, #64b5f6 60%, #1976d2 100%);
}

/* Drawer styles */
.drawer {
    position: fixed;
    top: 0;
    left: -220px;
    width: 220px;
    height: 100%;
    background: linear-gradient(135deg, #232526 60%, #485563 100%);
    box-shadow: 2px 0 16px rgba(0,0,0,0.18);
    padding-top: 60px;
    transition: left 0.3s;
    z-index: 1100;
    overflow: hidden;
}
.drawer.open {
    left: 0;
}
.drawer ul {
    list-style: none;
    padding: 0;
    margin: 0;
}
.drawer li {
    margin: 0;
    padding: 0;
}
.drawer a {
    display: block;
    padding: 18px 24px;
    color: #fff;
    text-decoration: none;
    font-size: 1.1rem;
    border-bottom: 1px solid #37474f;
    transition: background 0.2s;
}
.drawer a:hover {
    background: #1976d2;
}
#drawerBtn {
    position: fixed;
    top: 24px;
    left: 24px;
    z-index: 1200;
}

/* Responsive */
@media (max-width: 700px) {
    .calc-3d {
        max-width: 98vw;
        padding: 18px 6px 14px 6px;
    }
    .calc-display {
        font-size: 1.3rem;
        padding: 10px 8px;
    }
    .btn, .btn.adv {
        font-size: 0.95rem;
        padding: 10px 0;
    }
    .calc-buttons, .calc-advanced {
        gap: 7px;
    }
    .drawer {
        width: 70vw;
        left: calc(-1 * 70vw);
        overflow: hidden;
        min-width: 0;
        max-width: none;
    }
}
@media (max-width: 400px) {
    .calc-3d {
        padding: 8px 2px 8px 2px;
    }
    .calc-display {
        font-size: 1rem;
        padding: 7px 4px;
    }
    .btn, .btn.adv {
        font-size: 0.8rem;
        padding: 7px 0;
    }
    .calc-buttons, .calc-advanced {
        gap: 4px;
    }
    .drawer {
        width: 90vw;
        left: calc(-1 * 90vw);
        overflow: hidden;
        min-width: 0;
        max-width: none;
    }
}