/* Dark Unified Styling for Ephinea PSOBB Pages */

:root {
    --bg-primary: #0c1838;
    --bg-secondary: #1a2a4f;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #00d4ff;
    --accent-hover: #00b8d4;
    --accent-alt: #00a0ff;
    --accent-dark: #0a0e27;
    --heading-h1: #00d4ff;
    --heading-h2: #00d4ff;
    --heading-h3: #60a5fa;
    --heading-h4: #a78bfa;
    --link-color: #60a5fa;
    --border-color: rgba(255, 255, 255, 0.1);
    --accent-glow: rgba(0, 212, 255, 0.08);
    --accent-purple: rgba(138, 43, 226, 0.08);
    --accent-5: rgba(0, 212, 255, 0.05);
    --accent-10: rgba(0, 212, 255, 0.1);
    --accent-15: rgba(0, 212, 255, 0.15);
    --accent-20: rgba(0, 212, 255, 0.2);
    --accent-25: rgba(0, 212, 255, 0.25);
    --accent-30: rgba(0, 212, 255, 0.3);
    --accent-40: rgba(0, 212, 255, 0.4);
    --accent-50: rgba(0, 212, 255, 0.5);
    --accent-60: rgba(0, 212, 255, 0.6);
    /* 容器半透明色：从老主题 #1a2332 改成 PSO 蓝 #0c1838，
       并整体降低不透明度让 body 的 PSO bg.png 透出来。 */
    --bg-primary-75: rgba(12, 24, 56, 0.55);
    --bg-primary-80: rgba(12, 24, 56, 0.65);
    --bg-primary-60: rgba(12, 24, 56, 0.45);
    --table-header-bg: linear-gradient(135deg, rgba(0, 212, 255, 0.3), rgba(138, 43, 226, 0.3));
    --shadow-color: rgba(0, 0, 0, 0.25);
}

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

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    color: var(--text-primary);
    background-color: #000044;
    background-image: url('../img/bg/pso_isao_bg.png');
    background-repeat: repeat;
    background-attachment: fixed;
    position: relative;
}

/* 主页同款柔和角落 glow + 3px 软扫描线，无中央 vignette，让 PSO bg.png 显出来。 */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 55% at 95% -5%,  rgba(0, 212, 255, 0.13), transparent 55%),
        radial-gradient(ellipse 65% 55% at -5% 105%, rgba(110, 40, 210, 0.11), transparent 55%),
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 3px,
            rgba(0, 0, 0, 0.045) 3px,
            rgba(0, 0, 0, 0.045) 4px
        );
    z-index: 0;
    pointer-events: none;
}

body > * {
    position: relative;
    z-index: 1;
}

header {
    margin-bottom: 25px;
    text-align: center;
    width: 100%;
}

#project_title {
    color: var(--heading-h1);
    font-size: 2.8em;
    font-weight: 800;
    text-shadow: 0 0 20px var(--accent-50),
                 0 0 40px var(--accent-30);
    margin-bottom: 10px;
    letter-spacing: 2px;
}

.back-link {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent), var(--accent-alt));
    color: var(--accent-dark);
    padding: 14px 40px;
    border-radius: 50px;
    text-decoration: none;
    font-size: 17px;
    font-weight: 700;
    box-shadow: 0 0 30px var(--accent-40);
    transition: all 0.3s ease;
    margin-bottom: 35px;
    border: 2px solid var(--accent-30);
}

.back-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 40px var(--accent-60);
    background: linear-gradient(135deg, var(--accent-hover), var(--accent-alt));
}

.content-container {
    max-width: 1200px;
    width: 100%;
    background: var(--bg-primary-75);
    backdrop-filter: blur(3px);
    border: 1px solid var(--accent-30);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 8px 32px var(--shadow-color),
                inset 0 0 0 1px rgba(0, 130, 255, 0.06);
    line-height: 1.8;
}

.content-container h1 {
    color: var(--heading-h1);
    font-size: 2.2em;
    font-weight: 700;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 3px solid var(--accent-30);
}

.content-container h2 {
    color: var(--heading-h2);
    font-size: 1.8em;
    font-weight: 600;
    margin-top: 35px;
    margin-bottom: 18px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--accent-20);
}

.content-container h3 {
    color: var(--heading-h3);
    font-size: 1.4em;
    font-weight: 600;
    margin-top: 25px;
    margin-bottom: 15px;
}

.content-container h4 {
    color: var(--heading-h4);
    font-size: 1.2em;
    font-weight: 600;
    margin-top: 20px;
    margin-bottom: 12px;
}

.content-container p {
    color: var(--text-primary);
    margin-bottom: 15px;
    text-align: justify;
}

.content-container ul, .content-container ol {
    margin-left: 25px;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.content-container li {
    margin-bottom: 8px;
    line-height: 1.6;
}

.content-container a {
    color: var(--link-color);
    text-decoration: none;
    font-weight: 500;
    border-bottom: 1px solid transparent;
    transition: all 0.2s ease;
}

.content-container a:hover {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

.content-container table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    background: var(--bg-primary-60);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.content-container table thead {
    background: var(--table-header-bg);
    color: var(--text-primary);
}

.content-container table thead th {
    border: 1px solid var(--accent-30);
}

.content-container table th {
    padding: 12px 15px;
    text-align: left;
    font-weight: 600;
    border: 1px solid var(--accent-20);
    color: var(--text-primary);
}

.content-container table th[colspan] {
    text-align: center;
}

/* Diagonal split corner header: 右上/左下 两段文字 */
.content-container table th.diagonal-split {
    position: relative;
    min-width: 80px;
    min-height: 52px;
    padding: 4px;
    overflow: hidden;
}

.content-container table th.diagonal-split::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        45deg,
        transparent calc(50% - 1.5px),
        rgba(255, 255, 255, 0.35),
        transparent calc(50% + 1.5px)
    );
    pointer-events: none;
}

.content-container table th.diagonal-split .ds-top {
    position: absolute;
    top: 5px;
    left: 7px;
    font-size: 0.82em;
    line-height: 1;
}

.content-container table th.diagonal-split .ds-bot {
    position: absolute;
    bottom: 5px;
    right: 7px;
    font-size: 0.82em;
    line-height: 1;
}

.content-container table td {
    padding: 12px 15px;
    border: 1px solid var(--accent-10);
    color: var(--text-primary);
}

.content-container table tr:hover {
    background: var(--accent-5);
}

.content-container code {
    background: var(--accent-10);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent);
    font-size: 0.9em;
}

.content-container pre {
    background: rgba(0, 0, 0, 0.3);
    padding: 15px;
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: 15px;
    border: 1px solid var(--accent-15);
}

.content-container pre code {
    background: none;
    padding: 0;
}

.content-container blockquote {
    border-left: 4px solid var(--accent);
    padding-left: 20px;
    margin: 20px 0;
    color: var(--text-secondary);
    font-style: italic;
}

.content-container hr {
    border: none;
    border-top: 2px solid var(--accent-20);
    margin: 30px 0;
}

.content-container strong {
    color: var(--accent);
    font-weight: 600;
}

.content-container del {
    color: var(--text-muted);
}

.content-container img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
}

/* Navigation Menu Styles */
.nav-container {
    background: var(--bg-primary-80);
    border: 1px solid var(--accent-25);
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 30px;
    box-shadow: 0 8px 32px var(--shadow-color);
    backdrop-filter: blur(12px);
}

.nav-section {
    margin-bottom: 18px;
}

.nav-section:last-child {
    margin-bottom: 0;
}

.nav-title {
    color: var(--accent);
    font-weight: 600;
    font-size: 16px;
    margin-right: 12px;
    display: inline-block;
    text-shadow: 0 0 10px var(--accent-30);
}

.nav-links {
    display: inline-flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
}

.nav-link {
    background: var(--accent-10);
    color: var(--text-primary);
    padding: 6px 16px;
    border-radius: 20px;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    border: 1px solid var(--accent-20);
}

.nav-link:hover {
    background: var(--accent-20);
    color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Section anchors with offset */
.section-anchor {
    display: block;
    position: relative;
    top: -80px;
    visibility: hidden;
}

/* Back to Top Button */
#backToTop {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: linear-gradient(135deg, var(--accent), var(--accent-alt));
    color: var(--accent-dark);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    font-size: 24px;
    display: none;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 20px var(--accent-40);
    transition: all 0.3s ease;
    z-index: 1000;
}

#backToTop:hover {
    transform: translateY(-5px);
    box-shadow: 0 0 30px var(--accent-60);
}

#backToTop.show {
    display: flex;
}

@media (max-width: 768px) {
    #project_title {
        font-size: 2em;
    }

    .content-container {
        padding: 25px;
    }

    body {
        padding: 15px;
    }

    .nav-container {
        padding: 20px;
    }

    .nav-section {
        margin-bottom: 15px;
    }

    .nav-title {
        display: block;
        margin-bottom: 8px;
    }

    .nav-links {
        display: flex;
    }

    #backToTop {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
        font-size: 20px;
    }
}