:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-color: #333;
    --text-secondary: #666;
    --border-color: #e1e4e8;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.12);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
}

h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 8px;
}

.subtitle {
    font-size: 14px;
    color: var(--text-secondary);
}

.faq-list {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--card-bg);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: box-shadow 0.3s ease;
}

.faq-item:hover {
    box-shadow: var(--shadow-hover);
}

.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 18px 20px;
    background: var(--card-bg);
    border: none;
    cursor: pointer;
    text-align: left;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-color);
    transition: background-color 0.2s ease;
}

.faq-question:hover {
    background-color: #f8f9fa;
}

.faq-question[aria-expanded="true"] {
    background-color: #f0f7ff;
    color: var(--primary-color);
}

.question-text {
    flex: 1;
    padding-right: 15px;
}

.icon {
    font-size: 24px;
    font-weight: 300;
    color: var(--primary-color);
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.faq-question[aria-expanded="true"] .icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    background-color: #fafbfc;
}

.faq-answer.active {
    max-height: 1000px;
    padding: 20px;
    border-top: 1px solid var(--border-color);
}

.faq-answer p {
    font-size: 14px;
    line-height: 1.8;
    color: var(--text-secondary);
    white-space: pre-line;
}

footer {
    margin-top: 40px;
    padding: 20px 0;
    text-align: center;
    font-size: 12px;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
}

/* 移动端优化 */
@media (max-width: 600px) {
    .container {
        padding: 15px;
    }

    h1 {
        font-size: 24px;
    }

    .faq-question {
        padding: 15px;
        font-size: 15px;
    }

    .faq-answer.active {
        padding: 15px;
    }

    .faq-answer p {
        font-size: 13px;
    }
}

/* 平板和桌面端 */
@media (min-width: 768px) {
    .container {
        padding: 30px;
    }

    header {
        margin-bottom: 40px;
    }

    h1 {
        font-size: 32px;
    }

    .subtitle {
        font-size: 16px;
    }

    .faq-list {
        gap: 15px;
    }
}