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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    background-color: #f5f5f7;
    color: #1d1d1f;
    padding: 20px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1100px;
    margin: auto;
    overflow: hidden;
    background-color: #fff;
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.06);
}

h1, h2 {
    color: #1d1d1f;
    margin-bottom: 15px;
    text-align: center;
    font-weight: 600;
    letter-spacing: -0.02em;
}

h1 {
    margin-bottom: 25px;
    font-size: 2.5em;
}

.intro {
    text-align: center;
    margin-bottom: 40px;
    font-style: normal;
    color: #86868b;
    font-size: 1.1em;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.function-section {
    margin-bottom: 50px;
    padding: 30px;
    border-radius: 16px;
    background-color: #f5f5f7;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.function-section h2 {
    color: #1d1d1f;
    border-bottom: 2px solid #0071e3;
    display: inline-block;
    padding-bottom: 8px;
    margin-bottom: 20px;
}

.function-section > p {
    margin-bottom: 30px;
    text-align: center;
    color: #515154;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.section-content {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 30px;
}

.function-pair {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    padding: 20px;
    min-width: 180px;
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* Description Area Styling */
#description-area {
    border: none;
    background-color: #fff;
    padding: 25px;
    margin: 40px auto;
    border-radius: 16px;
    max-width: 80%;
    min-height: 180px;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
    position: relative;
}

#description-area h3 {
    margin-bottom: 12px;
    color: #1d1d1f;
    font-weight: 600;
    font-size: 1.3em;
}

#description-text {
    line-height: 1.5;
    margin-bottom: 15px;
    color: #515154;
}

#description-category {
    color: #86868b;
    font-size: 0.95em;
}

/* Selected state indicator */
#description-area.has-selection {
    box-shadow: 0 6px 20px rgba(0,0,0,0.12);
    background-color: #f8f8fc;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .section-content {
        flex-direction: column;
        align-items: center;
    }
    .function-pair {
       width: 90%;
       justify-content: space-around;
    }
     #description-area {
        max-width: 95%;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    .container {
        padding: 20px;
    }
    h1 {
        font-size: 1.8em;
    }
    h2 {
        font-size: 1.4em;
    }
    .function-shape {
        width: 60px;
        height: 60px;
        font-size: 1em;
    }
    .function-pair {
        gap: 15px;
    }
}