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

body{
    background-color: #faf8ef;
    color: #333;
    line-height: 1.6;
    padding: 20px;
    overflow-x: hidden;
}
.logo {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 10;
}

.logo a {
    color: #203354;
    font-size: 1.8rem;
    text-decoration: none;
    font-weight: bold;
}
.logo a:hover{
    color: #faf8ef;
    background: #203354;
    padding: 5px 15px;
    border-radius: 5px;
    transition: background 0.4s, color 0.3s;
}
.header{
    text-align: center;
    color: #203354;
    font-size: 3.5rem;
    font-weight: bold;
    margin: 40px 0;
    /*text-shadow: 2px 2px 8px rgba(32, 51, 84, .3);*/
    animation: fadeIn 1.5s ease-out;
}

.concepts-container{
   display: flex;
   flex-wrap: wrap;
   justify-content: center;
   gap: 20px;
   margin-top: 30px;
   padding: 20px;
   background: #fefbea;
   border-radius: 20px;
   box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
   border: 3px solid #203354;
   transition: box-shadow 0.3s;
}
.concepts-container:hover{
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2);
}
.concepts-header{
    width: 100%;
    text-align: center;
    font-size: 2.5rem;
    color: #203354;
    margin-bottom: 30px;
}
.concepts-content{
    display:flex;
    flex-direction: column;
    gap: 15px;
}
.concepts-item{
   background: #faf8ef;
   border: 2px solid #203354;
   border-radius: 15px;
   width: 300px;
   padding: 20px;
   text-align: center;
   box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
   transition: transform 0.3s, box-shadow 0.3s;
}
.concepts-item:hover{
   transform: scale(1.05);
   box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
   border-color: #67aaf1;
}
.concepts-item h3{
    font-size: 1.8rem;
    color: #203354;
    margin-bottom: 10px;
}
.concepts-item p {
    font-size: 1.2rem;
    color: #333;
    line-height: 1.6;
}
.container{
    display: flex;
    flex-direction: column;
    gap: 30px;
    align-items: center;
}
.what-is-it-container, .formula-container, .kinematics-calculator {
    width: calc(100% - 30px);
    background: #fefbea;
    border: 3px solid #203354;
    border-radius: 20px;
    padding: 20px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
    transition: transform 0.3s, box-shadow 0.3s;
}
.what-is-it-container:hover, 
.formula-container:hover, 
.kinematics-calculator:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.2);
}

.what,.concepts-header, .formula-header{
    font-size: 2rem;
    color: #203354;
    margin-bottom: 10px;
    text-align: center;
}
.def-what, .concepts-content{
    font-size: 1.2rem;
    color: #333;
}

.formula-box{
    background: #203354;
    color: #faf8ef;
    padding: 15px;
    border-radius: 10px;
    margin: 10px 0;
    font-family: 'Courier New', Courier, monospace;
    transition: background 0.3s;
}
.formula-box:hover{
    background: #67aaf1;
}

@media (max-width: 768px){
    .concepts-container, .what-is-it-container, .formula-container, .kinematics-calculator {
        width: 95%;
    }
    .concepts-content{
        flex-direction: column;
        align-items: center;
    }
    input[type="number"]{
        width: 100%;
    }
    button{
        width: 100%;
    }
}
form{
    display: flex;
    flex-direction: column;
    gap: 15px;
    padding: 20px;
    background: #faf8ef;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    max-width: 500px;
    margin: auto;
}

input,select{
    padding: 10px;
    font-size: 1rem;
    border: 2px solid #203354;
    border-radius: 5px;
    outline: none;
    transition: border-color 0.3s,box-shadow 0.3s;
}
input:focus,select:focus{
    border-color: #67aaf1;
    box-shadow: 0 0 10px rgba(103, 170, 241, 0.5);
}

button{
    padding: 12px 25px;
    font-size: 1.1rem;
    font-weight: bold;
    color: #faf8ef;
    background: #203354;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}
button:hover{
    background: #67aaf1;
    transform: scale(1.08);
}

.output{
    margin-top: 30px;
    padding: 20px;
    background: #faf8ef;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    text-align: center;
    font-size: 1.2rem;
}

#result{
    color: #203354;
    font-weight: bold;
    margin-bottom: 10px;
}

#equationUsed{
    font-style: italic;
    color: #555;
}

.kinematics-calculator h2 {
    text-align: center;
    font-size: 2rem;
    color: #203354;
    margin-bottom: 20px;
}