/* Color Palette: #E6F3FF, #ECFAFF, #F2FEFF, #F8FFFF, #FFF7FF */
:root {
    --color-bg-main: #f3fcff; /* Very light background */
    --color-bg-section: #F8FFFF;
    --color-bg-card: #F2FEFF;
    --color-accent-light: #ECFAFF;
    --color-border: #E6F3FF;
    --color-text-main: #333;
    --color-text-heading: #005A9C; /* A darker blue for contrast */
}

body {
    font-family: 'Times New Roman', Times, serif; 
    margin: 0;
    padding: 0;
    background-color: var(--color-bg-main);
    color: var(--color-text-main);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* --- Headings and Typography --- */
h1 {
    color: var(--color-text-heading);
    /* 移除 border-bottom 直线，创建波浪线效果 */
    border-bottom: none; 
    padding-bottom: 20px; 
    text-align: center;
    position: relative;
}

/* 伪元素创建波浪线 */
h1::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 10px; 
    background: 
        radial-gradient(circle at 5px -5px, transparent 10px, var(--color-accent-light) 10px), 
        radial-gradient(circle at 5px 15px, var(--color-accent-light) 10px, transparent 10px);
    background-size: 20px 20px; 
}

h2 {
    color: var(--color-text-heading);
    font-size: 1.8em;
    margin-top: 40px;
    border-left: 5px solid var(--color-border);
    padding-left: 10px;
}

h3 {
    color: #007ACC;
    font-size: 1.3em;
    margin-top: 25px;
}

/* --- Section and Card Layout --- */
.section-intro, .section-content {
    padding: 20px;
    margin-bottom: 20px;
    background-color: var(--color-bg-section);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.card {
    background-color: var(--color-bg-card);
    padding: 15px;
    border-radius: 6px;
    border-left: 3px solid #007ACC;
}

.card-list {
    margin: 10px 0 0;
    padding-left: 20px;
}

.card-list li {
    margin-bottom: 8px;
}

/* --- Show Case Layout (Requested Left/Right Boxes) --- */
.showcase-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-top: 30px;
}

.showcase-box {
    background-color: var(--color-accent-light);
    padding: 20px;
    border-radius: 8px;
    text-align: center;
    font-size: 1.2em;
    font-weight: bold;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* --- SQL x Tableau Workflow Steps --- */
.workflow-steps {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    margin-top: 20px;
}

.step {
    flex: 1 1 30%; 
    min-width: 250px;
    background-color: var(--color-bg-card);
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 5px;
    border-top: 4px solid var(--color-text-heading);
    box-sizing: border-box;
}

.step strong {
    display: block;
    font-size: 1.1em;
    margin-bottom: 5px;
    color: #007ACC;
}

/* --- Return Button Style --- */

.center-button {
    display: flex; 
    justify-content: center; 
    width: 100%; 
    /* ---------------------------------------------------- */
    /* 修改点: 减小上下外边距，让按钮更紧凑 */
    /* ---------------------------------------------------- */
    margin-top: 20px; /* 从 50px 减小到 20px */
    margin-bottom: 20px; /* 从 30px 减小到 20px */
}

.return-button {
    /* 基础样式 */
    display: inline-block;
    padding: 12px 30px;
    background-color: #ccffe4; 
    color: var(--color-text-heading); 
    font-weight: bold;
    text-decoration: none;
    border: none;
    border-radius: 25px;
    transition: background-color 0.3s, transform 0.1s;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.return-button:hover {
    background-color: #C3B1FF; 
    transform: translateY(-2px); 
}

.return-button:active {
    background-color: #96ffc2; 
    transform: translateY(0);
}

h1 {
    /* 1. 字体：使用优雅的 Didone 衬线字体栈 */
    font-family: "Bodoni", "Didot", "Times New Roman", Times, serif;
    
    /* 2. 字距：增加字母间距（可根据需要调整 0.2em 的值） */
    letter-spacing: 0.12em; 
    
    /* 3. 字重：确保标题醒目 */
    font-weight: 800; 
    font-size: 2.5em;
}