:root {
    --primary-color: #5A827E;
    --secondary-color: #84AE92;
    --accent-color: #B9D4AA;
    --background-color: #FAFFCA;
    --text-color: #333;
    --light-text-color: #555;
    --white-color: #ffffff;
    --dark-hover-color: #4A6E6A;
}

body {
    font-family: 'Open Sans', sans-serif;
    margin: 0;
    padding: 15px;
    background-color: var(--background-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    box-sizing: border-box;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-color);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: var(--secondary-color);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background-color: var(--accent-color);
    padding: 60px 40px;
    border-radius: 12px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.15);
    flex-grow: 1;
    min-height: 650px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

h1 {
    font-family: 'Montserrat', sans-serif;
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 40px;
    font-size: 2.5em;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.05);
}

.search-section {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 40px;
    width: 95%;
    max-width: 750px;
    margin-left: auto;
    margin-right: auto;
    position: relative;
}

#searchInput {
    flex-grow: 1;
    padding: 15px;
    border: 2px solid var(--secondary-color);
    border-radius: 8px;
    font-size: 1.1em;
    outline: none;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

#searchInput:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(90, 130, 126, 0.2);
}

#searchButton {
    padding: 15px 25px;
    background-color: var(--primary-color);
    color: var(--white-color);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.1em;
    font-weight: 600;
    transition: background-color 0.3s ease, transform 0.2s ease;
    margin-left: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
}

#searchButton:hover {
    background-color: var(--dark-hover-color);
    transform: translateY(-2px);
}

.initial-message,
.loading-message {
    text-align: center;
    font-size: 1.2em;
    color: var(--light-text-color);
    margin-top: 30px;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.spinner {
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.results-section {
    width: 100%;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 25px;
    justify-content: center;
    padding: 0 10px;
    align-items: stretch;
}

.results-section a {
    text-decoration: none;
    color: inherit;
    display: block;
    height: 100%;
}

.book-card {
    background-color: var(--secondary-color);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
    min-height: 450px;
    justify-content: space-between;
}

.results-section a:hover .book-card {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

.book-card img {
    max-width: 140px;
    height: auto;
    border-radius: 6px;
    margin-bottom: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.book-card img[src="https://via.placeholder.com/128x190?text=Tidak+Ada+Sampul"] {
    background-color: rgba(255, 255, 255, 0.7);
    border: 1px dashed var(--primary-color);
    display: flex;
    justify-content: center;
    align-items: center;
    color: var(--primary-color);
    font-size: 0.9em;
    text-align: center;
    line-height: 1.3;
    padding: 10px;
    height: 190px;
    width: 128px;
}

.book-card h3 {
    font-family: 'Montserrat', sans-serif;
    margin: 10px 0 8px;
    color: var(--text-color);
    font-size: 1.3em;
    line-height: 1.3;
    flex-grow: 0;
}

.book-card p {
    font-size: 0.95em;
    color: var(--light-text-color);
    margin-bottom: 8px;
    line-height: 1.4;
    flex-grow: 1;
}

@media (max-width: 1024px) {
    .container {
        padding: 50px 30px;
        max-width: 95%;
        min-height: 600px;
    }
    h1 {
        font-size: 2.2em;
    }
    .search-section {
        max-width: 650px;
    }
    .book-card {
        min-height: 420px;
    }
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    .container {
        padding: 40px 25px;
        max-width: 98%;
        min-height: 550px;
    }
    h1 {
        font-size: 2em;
        margin-bottom: 30px;
    }
    .search-section {
        width: 100%;
        max-width: none;
        flex-wrap: wrap;
        justify-content: center;
    }
    #searchInput {
        flex-grow: 1;
        width: 100%;
        border-radius: 8px;
        margin-bottom: 10px;
        order: 1;
        padding-right: 15px;
    }
    #searchButton {
        width: 100%;
        margin-left: 0;
        order: 3;
        justify-content: center;
    }
    .results-section {
        grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
        gap: 15px;
    }
    .book-card {
        min-height: 400px;
    }
    .book-card img {
        max-width: 100px;
    }
    .book-card img[src="https://via.placeholder.com/128x190?text=Tidak+Ada+Sampul"] {
        height: 150px;
        width: 100px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 5px;
    }
    .container {
        padding: 30px 15px;
        min-height: 480px;
        border-radius: 8px;
    }
    h1 {
        font-size: 1.8em;
        margin-bottom: 25px;
    }
    #searchInput {
        font-size: 1em;
        padding: 12px;
    }
    #searchButton {
        padding: 12px 20px;
        font-size: 1em;
    }
    .results-section {
        grid-template-columns: 1fr;
        gap: 15px;
        padding: 0;
    }
    .book-card {
        min-height: auto;
    }
    .book-card h3 {
        font-size: 1.1em;
    }
    .book-card p {
        font-size: 0.85em;
    }
}