:root {
    --primary-color: #4CAF50;
    --primary-dark: #45a049;
    --secondary-color: #2c3e50;
    --light-gray: #f5f5f5;
    --card-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --hover-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    --border-color: #e0e0e0;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--light-gray);
    color: #333;
}

.content-container {
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 1000px;
    margin: 20px auto;
}

h1 {
    text-align: center;
    color: var(--secondary-color);
    margin-bottom: 20px;
    font-size: 2rem;
}

p {
    margin: 15px 0;
}

.formula {
    margin: 20px 0;
    padding: 15px;
    background-color: #f9f9f9;
    border-radius: 4px;
    border-left: 4px solid var(--primary-color);
}

button {
    background-color: var(--primary-color);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    margin: 10px 0;
    transition: background-color 0.3s, transform 0.2s;
}

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

button:active {
    transform: translateY(0);
}

.container {
    max-width: 100%;
    margin: 30px auto 0;
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    padding: 20px;
}

.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.card {
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    padding: 20px;
    transition: transform 0.3s, box-shadow 0.3s;
    border: 1px solid var(--border-color);
    position: relative;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--hover-shadow);
}

.card.selected {
    border: 2px solid var(--primary-color);
    background-color: #f0f9f0;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.card-title {
    font-weight: 600;
    color: var(--secondary-color);
    margin: 0;
    font-size: 1.2rem;
}

.card-date {
    color: #7f8c8d;
    font-size: 0.9em;
    margin-top: 10px;
}

.notification {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--primary-color);
    color: white;
    padding: 15px 25px;
    border-radius: 4px;
    display: none;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
    z-index: 1000;
    animation: slideIn 0.3s forwards;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

#detailsContainer {
    margin-top: 30px;
    padding: 20px;
    background-color: #f9f9f9;
    border-radius: 8px;
    display: none;
    border-left: 4px solid var(--primary-color);
}

#detailsTable {
    width: 100%;
    border-collapse: collapse;
    margin-top: 15px;
}

#detailsTable th, #detailsTable td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

#detailsTable th {
    background-color: #f2f2f2;
    font-weight: 600;
    color: var(--secondary-color);
}

#detailsTable tr:last-child td {
    border-bottom: none;
}

/* 响应式设计 */
@media (max-width: 768px) {
    body {
        padding: 15px;
    }

    h1 {
        font-size: 1.8rem;
    }

    p {
        font-size: 1rem;
    }

    .formula-container {
        padding: 15px;
    }

    #downloadBtn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
}

/* 针对手机小屏幕的额外优化 */
@media (max-width: 480px) {
    body {
        font-size: calc(var(--base-font-size) + 2px); /* 增加基础字体大小 */
    }

    h1 {
        font-size: 1.6rem;
        margin-bottom: 15px;
    }

    p {
        font-size: 1.1rem;
        margin-bottom: 12px;
    }

    .formula-container {
        padding: 15px;
        margin: 15px 0;
    }

    .independent-formula {
        font-size: 1.1rem;
    }

    #downloadBtn {
        width: 100%;
        padding: 12px;
        font-size: 1rem;
    }
}

/* 非常小的屏幕，如某些手机型号 */
@media (max-width: 320px) {
    body {
        font-size: calc(var(--base-font-size) + 3px); /* 进一步增加字体大小 */
    }

    h1 {
        font-size: 1.4rem;
    }

    p {
        font-size: 1rem;
    }

    .formula-container {
        padding: 10px;
    }
}

.accordion {
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
}

.accordion-item {
    margin-bottom: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    overflow: hidden;
}

.accordion-header {
    background-color: #f1f1f1;
    padding: 15px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.accordion-header:hover {
    background-color: #ddd;
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background-color: #fff;
    padding: 0 15px;
}

.accordion-content p {
    padding: 15px 0;
}


.pagination {
    margin-top: 20px;
    text-align: center;
}
.pagination a {
    margin: 0 10px;
    text-decoration: none;
    color: #0066cc;
}
.pagination span {
    margin: 0 10px;
}


.formula {
    background-color: #f8f9fa;
    padding: 15px;
    border-radius: 5px;
    margin: 20px 0;
    border-left: 4px solid #3498db;
}
.parameter {
    margin: 5px 0;
    padding: 5px 10px;
    background-color: #eaf2f8;
    border-radius: 3px;
}
.parameter strong {
    color: #2980b9;
}

footer {
    background-color: #f1f1f1;
    padding: 10px 20px;
    text-align: center;
    position: relative;
    bottom: 0;
    width: 100%;
}

.version {
    font-size: 14px;
    color: #666;
}

#deleteBtn {
    background-color: #f44336;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    margin: 10px 0 10px 10px;
    transition: background-color 0.3s, transform 0.2s;
}

#deleteBtn:hover {
    background-color: #d32f2f;
    transform: translateY(-2px);
}

#deleteBtn:active {
    transform: translateY(0);
}

.pagination {
    margin-top: 20px;
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
}

.pagination button {
    background-color: var(--primary-color);
    color: white;
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

.pagination button:hover:not(:disabled) {
    background-color: var(--primary-dark);
}

.pagination button:disabled {
    background-color: #cccccc;
    cursor: not-allowed;
    opacity: 0.6;
}

.pagination span {
    margin: 0 10px;
    font-size: 14px;
}