@import "https://fonts.googleapis.com/css2?family=Noto+Serif+Thai:wght@400;600&family=Sarabun:wght@400;500;600&display=swap";:root{--desk-bg:#f0ebe1;--paper-bg:#fdfbf7;--ink-main:#2c2a29;--ink-light:#5a5755;--accent-color:#8c2121;--accent-muted:#8c21210d;--border-line:#e2dfd8;--shadow-sm:0 2px 8px #0000000a;--shadow-md:0 12px 24px #0000000f;--shadow-lg:0 25px 50px #00000014;--font-heading:"Noto Serif Thai", serif;--font-body:"Sarabun", sans-serif;--transition:.4s cubic-bezier(.16, 1, .3, 1)}*{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth;font-size:18px}body{background-color:var(--desk-bg);color:var(--ink-main);font-family:var(--font-body);background-image:url("data:image/svg+xml,%3Csvg width=\"100\" height=\"100\" xmlns=\"http://www.w3.org/2000/svg\"%3E%3Cfilter id=\"noise\"%3E%3CfeTurbulence type=\"fractalNoise\" baseFrequency=\"0.9\" numOctaves=\"3\" stitchTiles=\"stitch\"/%3E%3C/filter%3E%3Crect width=\"100\" height=\"100\" filter=\"url(%23noise)\" opacity=\"0.06\"/%3E%3C/svg%3E");line-height:1.8}h1,h2,h3,h4,h5,h6{font-family:var(--font-heading);color:var(--ink-main);font-weight:600;line-height:1.4}a{color:var(--accent-color);transition:var(--transition);text-decoration:none}a:hover{color:var(--ink-main)}.book-container{background-color:var(--paper-bg);max-width:900px;box-shadow:var(--shadow-lg), 0 0 0 1px #00000005;border-radius:4px;min-height:80vh;margin:40px auto;padding:60px 50px;position:relative}.book-container:before,.book-container:after{content:"";z-index:-1;width:40%;height:20px;transition:var(--transition);position:absolute;bottom:15px;box-shadow:0 15px 10px #00000014}.book-container:before{left:20px;transform:rotate(-2deg)}.book-container:after{right:20px;transform:rotate(2deg)}.book-header{text-align:center;margin-bottom:60px;padding-bottom:20px}.book-title{letter-spacing:-.02em;text-shadow:1px 1px #fff,-1px -1px #0000000d;margin-bottom:15px;font-size:3rem}.book-subtitle{font-family:var(--font-heading);color:var(--ink-light);margin-bottom:30px;font-size:1.2rem;font-style:italic}.header-divider{background-color:var(--accent-color);width:60px;height:2px;margin:0 auto;box-shadow:0 2px 4px #8c212133}.table-of-contents{border:1px solid var(--border-line);box-shadow:inset 0 2px 10px #00000005, var(--shadow-sm);background-color:#fafaf7;border-radius:4px;margin-bottom:40px;padding:40px}.concept-list{flex-direction:column;gap:15px;display:flex}.concept-item{border:1px solid var(--border-line);box-shadow:var(--shadow-sm);transition:var(--transition);background-color:#fff;border-radius:6px;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:15px;padding:24px;display:flex}.concept-item:hover{border-color:var(--ink-light);box-shadow:var(--shadow-md);transform:translateY(-2px)}.slide-info{flex:1;min-width:250px}.slide-info h3{color:var(--accent-color);align-items:center;gap:10px;margin-bottom:4px;font-size:1.25rem;display:flex}.slide-icon{color:var(--ink-light);display:flex}.slide-actions{gap:10px;display:flex}.btn{border:1px solid var(--border-line);color:var(--ink-main);font-family:var(--font-body);cursor:pointer;transition:var(--transition);white-space:nowrap;background:0 0;border-radius:4px;align-items:center;gap:6px;padding:8px 16px;font-size:.95rem;font-weight:500;display:inline-flex}.btn:hover{border-color:var(--ink-main);background-color:var(--desk-bg)}.btn-primary{background-color:var(--accent-color);color:#fff;border-color:var(--accent-color)}.btn-primary:hover{color:#fff;background-color:#701919;border-color:#701919}.viewer-overlay{-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);z-index:100;background:#2c2a29f2;flex-direction:column;width:100vw;height:100vh;display:flex;position:fixed;top:0;left:0}.viewer-header{color:#fdfdfd;background:#1a1a1a;border-bottom:1px solid #333;justify-content:space-between;align-items:center;padding:15px 30px;display:flex}.viewer-header h2{color:#fdfdfd;font-size:1.2rem;font-weight:400;font-family:var(--font-body)}.close-btn{color:#fff;cursor:pointer;background:0 0;border:none;font-size:2.5rem;line-height:1;transition:color .2s}.close-btn:hover{color:var(--accent-color)}.viewer-content{background:#333;flex:1;width:100%;height:100%}.viewer-content iframe{border:none;width:100%;height:100%}@media (width<=768px){body{padding:0}.book-container{box-shadow:none;border-radius:0;min-height:100vh;margin:0;padding:30px 15px}.book-container:before,.book-container:after{display:none}.table-of-contents{padding:25px 15px}.book-title{font-size:2.2rem}.concept-item{flex-direction:column;align-items:stretch}.slide-actions{flex-flow:wrap;gap:8px;width:100%;display:flex}.btn{flex:1;justify-content:center;min-width:120px;padding:12px 8px;font-size:.9rem}}