:root {
    /* --- Layout Variables --- */
    --sidebar-width: 320px;
    --content-width: 800px;
    --font-size: 16px;

    /* --- Theme Colors --- */
    --light-bg: #ffffff;
    --light-text: #333333;
    --light-sidebar-bg: #f8f9fa;
    --light-border: #dee2e6;
    --light-code-bg: #f1f3f5;


    --dark-bg: #1a1a1a;
    --dark-text: #e0e0e0;
    --dark-sidebar-bg: #2d2d2d;
    --dark-border: #495057;
    --dark-code-bg : #0d1117;

    /* --- Accent Colors --- */
    --primary-accent: #08478a;
    --primary-accent-hover: #ffffff;
    --dark-primary-accent: #5298d1;
    --dark-primary-accent-hover: #1a1a1a;
}





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

html, body { height: 100%; overflow: hidden; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: var(--font-size);
    line-height: 1.7;
    transition: background-color 0.3s, color 0.3s;
}

#markdown-reader-container { display: flex; height: 100%; }

/* --- Scrollbar Styles --- */
::-webkit-scrollbar { width: 12px; height: 12px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { border-radius: 6px; }
body.light ::-webkit-scrollbar-thumb { background-color: #d1d5db; border: 3px solid var(--light-bg); }
body.light ::-webkit-scrollbar-thumb:hover { background-color: #9ca3af; }
body.dark ::-webkit-scrollbar-thumb { background-color: #4b5563; border: 3px solid var(--dark-bg); }
body.dark ::-webkit-scrollbar-thumb:hover { background-color: #6b7280; }
#toc-list::-webkit-scrollbar-thumb { border-color: transparent; }

/* --- Theme Application --- */
body.light { background-color: var(--light-bg); color: var(--light-text); }
body.dark { background-color: var(--dark-bg); color: var(--dark-text); }

.open-sidebar-btn { position: fixed; left: 10px; top: 15px; z-index: 1000; border: 1px solid; border-radius: 6px; width: 40px; height: 40px; font-size: 24px; cursor: pointer; display: none; align-items: center; justify-content: center; transition: all 0.3s; }
body.light .open-sidebar-btn { background: var(--light-bg); border-color: var(--light-border); }
body.dark .open-sidebar-btn { background: var(--dark-sidebar-bg); border-color: var(--dark-border); color: var(--dark-text); }
body.sidebar-collapsed .open-sidebar-btn { display: flex; }

.sidebar { width: var(--sidebar-width); min-width: 380px; max-width: 600px; border-right: 1px solid; display: flex; flex-direction: column; transition: margin-left 0.3s ease, width 0.3s ease; height: 100vh; flex-shrink: 0; position: relative; }
.sidebar.collapsed { min-width: 0px; margin-left: calc(-1 * var(--sidebar-width)); }
body.light .sidebar { background-color: var(--light-sidebar-bg); border-color: var(--light-border); }
body.dark .sidebar { background-color: var(--dark-sidebar-bg); border-color: var(--dark-border); }

.sidebar-header { padding: 20px; border-bottom: 1px solid; flex-shrink: 0; position: relative; }
body.light .sidebar-header { border-color: var(--light-border); }
body.dark .sidebar-header { border-color: var(--dark-border); }

.sidebar-content { flex: 1; padding: 20px; display: flex; flex-direction: column; min-height: 0; }
.main-content { flex: 1; overflow-y: auto; height: 100vh; padding: 40px; scroll-behavior: smooth; }
.main-content.is-loading { visibility: hidden; }

.header { display: flex; justify-content: space-between; align-items: center; gap: 15px; }
.sidebar-toggle { background: none; border: none; cursor: pointer; font-size: 24px; padding: 5px; opacity: 0.7; transition: opacity 0.2s; }
.sidebar-toggle:hover { opacity: 1; }
body.light .sidebar-toggle { color: var(--light-text); }
body.dark .sidebar-toggle { color: var(--dark-text); }

.header-controls { display: flex; gap: 10px; align-items: center; }
.control-button { background: none; border: 2px solid; border-radius: 6px; padding: 6px 12px; cursor: pointer; transition: all 0.3s; font-size: 12px; white-space: nowrap; }
body.light .control-button { border-color: var(--primary-accent); color: var(--primary-accent); }
body.dark .control-button { border-color: var(--dark-primary-accent); color: var(--dark-primary-accent); }
.control-button:hover { transform: translateY(-1px); box-shadow: 0 2px 8px rgba(0,0,0,0.2); }
body.light .control-button:hover { background-color: var(--primary-accent); color: var(--primary-accent-hover); }
body.dark .control-button:hover { background-color: var(--dark-primary-accent); color: var(--dark-primary-accent-hover); }

.settings-panel { position: absolute; top: 100%; right: 20px; border: 1px solid; border-radius: 8px; padding: 15px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); z-index: 1010; width: 280px; display: none; }
body.light .settings-panel { background: var(--light-bg); border-color: var(--light-border); }
body.dark .settings-panel { background: var(--dark-sidebar-bg); border-color: var(--dark-border); }
.settings-panel.visible { display: block; }
.settings-panel h4 { margin-top: 0; margin-bottom: 15px; }
.setting { margin-bottom: 15px; }
.setting label { display: block; margin-bottom: 5px; font-size: 13px; }
.setting input[type="range"], .setting select { width: 100%; }

.settings-panel-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 15px; }
.close-settings { background: none; border: none; font-size: 18px; cursor: pointer; opacity: 0.7; padding: 0; width: 24px; height: 24px; display: flex; align-items: center; justify-content: center; }
.close-settings:hover { opacity: 1; }
body.light .close-settings { color: var(--light-text); }
body.dark .close-settings { color: var(--dark-text); }
.settings-panel.visible ~ .header .settings-toggle { display: none; }

.file-info { flex: 1; min-width: 0; }
.file-info strong, .file-info .breadcrumb { display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.file-info strong { font-size: 16px; margin-bottom: 4px; }
.file-info .breadcrumb { font-size: 12px; opacity: 0.7; }

.quick-links { margin-bottom: 20px; flex-shrink: 0; }
.quick-links h3 { margin-bottom: 10px; font-size: 14px; }
.quick-links-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(100px, 1fr)); gap: 8px; }
.quick-link { text-decoration: none; padding: 8px 12px; border-radius: 6px; display: block; transition: all 0.2s; font-size: 13px; text-align: center; border: 1px solid; }
body.light .quick-link { color: var(--light-text); border-color: var(--light-border); background-color: var(--light-bg); }
body.dark .quick-link { color: var(--dark-text); border-color: var(--dark-border); background-color: var(--dark-sidebar-bg); }
body.light .quick-link:hover { background-color: #e9ecef; }
body.dark .quick-link:hover { background-color: #495057; }
body.light .quick-link.active { background-color: #e3f2fd; color: var(--primary-accent); border-color: var(--primary-accent); font-weight: bold; }
body.dark .quick-link.active { background-color: #1e3a8a; color: var(--dark-primary-accent); border-color: var(--dark-primary-accent); font-weight: bold; }

.toc { flex: 1; display: flex; flex-direction: column; min-height: 0; }
.toc h3 { margin-bottom: 15px; font-size: 14px; flex-shrink: 0; }
#toc-search { width: 100%; padding: 8px; margin-bottom: 15px; border-radius: 4px; border: 1px solid; font-size: 13px; flex-shrink: 0; }
body.light #toc-search { border-color: var(--light-border); background-color: var(--light-bg); color: var(--light-text); }
body.dark #toc-search { border-color: var(--dark-border); background-color: var(--dark-sidebar-bg); color: var(--dark-text); }
#toc-list { list-style: none; overflow-y: auto; flex: 1; }
.toc li { margin-bottom: 4px; }
.toc a { text-decoration: none; padding: 6px 10px; border-radius: 4px; display: block; transition: all 0.2s; font-size: 13px; border-left: 3px solid transparent; }
body.light .toc a { color: var(--light-text); } 
body.dark .toc a { color: var(--dark-text); }
body.light .toc a.active, body.light .toc a:hover { background-color: #e3f2fd; color: var(--primary-accent); border-left-color: var(--primary-accent); }
body.dark .toc a.active, body.dark .toc a:hover { background-color: #3c3c3c; color: var(--dark-primary-accent); border-left-color: var(--dark-primary-accent); }
.toc .h1 { padding-left: 10px; font-weight: 600; } 
.toc .h2 { padding-left: 20px; } 
.toc .h3 { padding-left: 30px; } 
.toc .h4 { padding-left: 40px; } 
.toc .h5 { padding-left: 50px; } 
.toc .h6 { padding-left: 60px; }

.markdown-content { max-width: var(--content-width); margin: 0 auto; transition: max-width 0.3s ease-in-out; }
.main-content.welcome-container { display: flex; align-items: center; justify-content: center; padding: 40px; }

.loading-container { text-align: center; max-width: 500px; padding: 30px; border-radius: 12px; border: 1px solid; }
body.light .loading-container { background-color: var(--light-sidebar-bg); border-color: var(--light-border); }
body.dark .loading-container { background-color: var(--dark-sidebar-bg); border-color: var(--dark-border); }
.loading-container p { margin-bottom: 1.2em; line-height: 1.6; }
.loading-container a { text-decoration: none; font-weight: 500; border-bottom: 1px dashed; }
body.light .loading-container a { color: var(--primary-accent); }
body.dark .loading-container a { color: var(--dark-primary-accent); }
.loading-container a:hover { text-decoration: none; border-bottom-style: solid; }

.markdown-content p, .markdown-content ul, .markdown-content ol, .markdown-content blockquote, .markdown-content pre { margin-bottom: 1.5em; }
.markdown-content h1, .markdown-content h2, .markdown-content h3, .markdown-content h4, .markdown-content h5, .markdown-content h6 { scroll-margin-top: 20px; margin-bottom: 0.8em; }
.markdown-content h1 { margin-top: 0; }
.markdown-content h2 { margin-top: 2.5em; }
.markdown-content h3 { margin-top: 2em; }
.sidebar-resizer { position: absolute; right: -2.5px; top: 0; bottom: 0; width: 5px; cursor: ew-resize; z-index: 10; }
.drop-zone { position: fixed; top: 0; left: 0; width: 100%; height: 100%; z-index: 10000; background: rgba(0, 123, 255, 0.1); border: 3px dashed var(--primary-accent); display: none; align-items: center; justify-content: center; font-size: 24px; color: var(--primary-accent); } 
.drop-zone.visible { display: flex; }

@media (max-width: 768px) { 
    #markdown-reader-container { flex-direction: column; } 
    .sidebar { position: fixed; z-index: 999; width: 280px !important; box-shadow: 2px 0 10px rgba(0,0,0,0.1); } 
    .sidebar.collapsed { margin-left: -280px; } 
    .main-content { width: 100%; } 
    .sidebar-toggle { display: flex !important; } 
}

.markdown-content h1 { font-size: 2.5em; border-bottom: 1px solid; padding-bottom: 0.3em; } 
body.light .markdown-content h1 { border-color: var(--light-border); }
body.dark .markdown-content h1 { border-color: var(--dark-border); }
.markdown-content h2 { font-size: 2em; border-bottom: 1px solid; padding-bottom: 0.3em; } 
body.light .markdown-content h2 { border-color: var(--light-border); }
body.dark .markdown-content h2 { border-color: var(--dark-border); }
.markdown-content h3 { font-size: 1.5em; } 
.markdown-content pre { position: relative; padding: 1em; border-radius: 6px; }
body.light .markdown-content pre { background-color: var(--light-code-bg); }
body.dark .markdown-content pre {  background-color: var(--dark-code-bg);  }


.copy-code-button { position: absolute; top: 10px; right: 10px; background: #6c757d; color: white; border: none; padding: 4px 8px; border-radius: 4px; cursor: pointer; opacity: 0; transition: opacity 0.2s; } 
.markdown-content pre:hover .copy-code-button { opacity: 1; } 
.back-to-top { position: fixed; bottom: 30px; right: 30px; width: 50px; height: 50px; border-radius: 50%; border: none; cursor: pointer; font-size: 20px; opacity: 0; visibility: hidden; z-index: 1000; transition: opacity 0.3s, visibility 0.3s; } 
.back-to-top.visible { opacity: 1; visibility: visible; } 
body.light .back-to-top { background-color: var(--primary-accent); color: var(--primary-accent-hover); } 
body.dark .back-to-top { background-color: var(--dark-primary-accent); color: var(--dark-primary-accent-hover); } 
.progress-indicator { position: fixed; top: 0; left: 0; width: 0%; height: 3px; background: var(--primary-accent); z-index: 1001; }
body.dark .progress-indicator { background: var(--dark-primary-accent); }

/* --- HR Spacing and Style --- */
.markdown-content hr {
    border: 0;
    height: 1px;
    margin: 3.5em 0;
}
body.light .markdown-content hr { background-color: var(--light-border); }
body.dark .markdown-content hr { background-color: var(--dark-border); }