/* =========================================================
   GLOBAL VARIABLES & BRANDING
   ========================================================= */
:root {
    --bg-dark: #0B1120;
    --bg-panel: #111827;
    --bg-card: #1E293B;
    --text-main: #F1F5F9;
    --text-muted: #94A3B8;
    --accent-blue: #38BDF8;
    --accent-red: #F43F5E;
    --accent-green: #10B981;
    --accent-orange: #FB923C;
    --border-color: #334155;
    --grid-color: rgba(56, 189, 248, 0.1);
}

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

body, .reveal-viewport, .reveal {
    font-family: 'Inter', sans-serif !important;
    background-color: var(--bg-dark) !important;
    color: var(--text-main) !important;
    overflow: hidden;
}

.grid-bg {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-image: linear-gradient(var(--grid-color) 1px, transparent 1px),
                      linear-gradient(90deg, var(--grid-color) 1px, transparent 1px);
    background-size: 40px 40px; z-index: 0; pointer-events: none; opacity: 0.4;
}

.glow-spot {
    position: fixed; width: 800px; height: 800px;
    background: radial-gradient(circle, rgba(56, 189, 248, 0.08) 0%, transparent 70%);
    top: 50%; left: 50%; transform: translate(-50%, -50%);
    z-index: 0; pointer-events: none;
}

.reveal .slides section { height: 100%; width: 100%; padding: 0; text-align: left; }

header {
    padding: 40px 70px 20px; border-bottom: 1px solid var(--border-color);
    display: flex; justify-content: space-between; align-items: flex-end;
    position: relative; z-index: 1;
}

.page-title { font-size: 36px; font-weight: 700; letter-spacing: -0.5px; color: var(--text-main); margin:0;}
.page-subtitle { color: var(--accent-blue); font-size: 16px; font-family: 'JetBrains Mono', monospace; margin:0; font-weight: 700;}
.main-content { padding: 40px 70px; height: calc(100% - 110px); display: flex; flex-direction: column; position: relative; z-index: 1;}

.highlight-blue { color: var(--accent-blue); font-weight: 600; }
.highlight-red { color: var(--accent-red); font-weight: 600; }
.highlight-green { color: var(--accent-green); font-weight: 600; }
.highlight-orange { color: var(--accent-orange); font-weight: 600; }

/* =========================================================
   SLIDE CONTENT STYLES
   ========================================================= */
.layout-split { display: flex; gap: 40px; height: 100%; align-items: stretch; }
.content-col { flex: 1; display: flex; flex-direction: column; justify-content: flex-start; }
.visual-col { flex: 1; display: flex; align-items: center; justify-content: center; }

.info-card { background: var(--bg-card); border: 1px solid var(--border-color); padding: 25px; border-radius: 8px; margin-bottom: 20px; }
.info-card h4 { font-family: 'JetBrains Mono'; font-size: 14px; color: var(--accent-blue); margin-bottom: 10px; border-bottom: 1px solid var(--border-color); padding-bottom: 5px;}
.info-card p, .info-card ul { font-size: 15px; color: var(--text-muted); line-height: 1.6; }
.info-card ul { padding-left: 20px; }
.info-card li { margin-bottom: 8px; }

.image-placeholder {
    width: 100%; height: 90%; border: 2px dashed var(--border-color); border-radius: 12px;
    background: rgba(30, 41, 59, 0.4); display: flex; flex-direction: column; align-items: center;
    justify-content: center; color: var(--text-muted); font-family: 'JetBrains Mono'; font-size: 14px;
    text-align: center; padding: 20px; transition: 0.3s;
}
.image-placeholder i { font-size: 48px; color: var(--border-color); margin-bottom: 15px; }
.image-placeholder:hover { border-color: var(--accent-blue); background: rgba(56, 189, 248, 0.05); color: var(--accent-blue); }
.image-placeholder:hover i { color: var(--accent-blue); }

/* =========================================================
   THE ENGINEERING DRAWER & UI ELEMENTS
   ========================================================= */
.derivation-trigger {
    position: absolute; top: 35px; right: 70px; z-index: 50;
    background: rgba(56, 189, 248, 0.1); border: 1px solid var(--accent-blue);
    color: var(--accent-blue); font-family: 'JetBrains Mono', monospace;
    padding: 10px 20px; border-radius: 4px; font-size: 14px; font-weight: 700;
    cursor: pointer; display: flex; align-items: center; gap: 10px;
    box-shadow: 0 0 15px rgba(56, 189, 248, 0.2); transition: all 0.3s ease;
}
.derivation-trigger:hover { background: rgba(56, 189, 248, 0.2); box-shadow: 0 0 25px rgba(56, 189, 248, 0.4); color: #fff;}

#engineering-drawer {
    position: fixed; top: 0; right: -750px; width: 700px; height: 100%;
    background: rgba(17, 24, 39, 0.95); backdrop-filter: blur(20px);
    border-left: 1px solid var(--accent-blue); z-index: 100;
    transition: right 0.5s cubic-bezier(0.16, 1, 0.3, 1);
    padding: 40px; overflow-y: auto; box-shadow: -20px 0 50px rgba(0,0,0,0.6);
    display: flex; flex-direction: column;
}
#engineering-drawer.open { right: 0; }

.close-drawer {
    position: absolute; top: 25px; right: 25px; background: transparent; border: none; 
    color: var(--text-muted); font-size: 24px; cursor: pointer; transition: color 0.3s;
}
.close-drawer:hover { color: var(--accent-red); }

.drawer-label { font-family: 'JetBrains Mono', monospace; font-size: 12px; color: var(--accent-blue); margin-bottom: 5px; }
.drawer-title { font-size: 28px; font-weight: 700; color: var(--text-main); margin-bottom: 20px; border-bottom: 1px solid var(--border-color); padding-bottom: 15px;}

.drawer-nav { display: flex; gap: 5px; margin-bottom: 25px; border-bottom: 2px solid var(--border-color); }
.drawer-tab-btn { background: none; border: none; color: var(--text-muted); font-family: 'JetBrains Mono'; font-size: 12px; font-weight: 700; padding: 10px 15px; cursor: pointer; border-bottom: 2px solid transparent; transition: 0.3s; margin-bottom: -2px;}
.drawer-tab-btn:hover { color: var(--text-main); }
.drawer-tab-btn.active { color: var(--accent-blue); border-bottom: 2px solid var(--accent-blue); }

.drawer-view { display: none; animation: fadeIn 0.4s; }
.drawer-view.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }

.drawer-text { font-size: 14px; color: #cbd5e1; line-height: 1.6; margin-bottom: 15px; }
.drawer-text ul, .drawer-text ol { padding-left: 20px; margin-bottom: 15px; }
.drawer-text li { margin-bottom: 8px; }
.math-box { background: rgba(0,0,0,0.5); border: 1px solid var(--border-color); border-left: 3px solid var(--accent-blue); border-radius: 6px; padding: 20px; margin: 20px 0; overflow-x: auto; font-size: 18px; color: #fff; }

/* Custom Nav */
.custom-nav { position: fixed; bottom: 30px; right: 70px; z-index: 90; display: flex; gap: 10px; }
.nav-btn { background: var(--bg-panel); border: 1px solid var(--border-color); color: var(--text-main); width: 40px; height: 40px; border-radius: 50%; cursor: pointer; transition: 0.3s; display: flex; align-items: center; justify-content: center; }
.nav-btn:hover { background: var(--accent-blue); border-color: var(--accent-blue); }

/* Custom Slide Numbering */
.custom-slide-number {
    position: absolute;
    bottom: 40px;
    left: 70px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 14px;
    font-weight: 700;
    color: var(--text-muted);
    z-index: 10;
    letter-spacing: 1px;
}
.custom-slide-number span { color: var(--border-color); }

/* Master Matrix Table */
.view-toggle { display: flex; gap: 10px; margin-bottom: 15px; flex-wrap: wrap;}
.view-btn { background: var(--bg-dark); border: 1px solid var(--border-color); color: var(--text-muted); padding: 5px 15px; border-radius: 4px; font-family: 'JetBrains Mono'; font-size: 12px; cursor: pointer; transition: 0.3s; }
.view-btn.active { background: var(--accent-blue); color: #fff; border-color: var(--accent-blue); }
.data-view { display: none; width: 100%; height: 100%; animation: fadeIn 0.4s; }
.data-view.active { display: block; }

.master-table { width: 100%; border-collapse: collapse; font-size: 12px; }
.master-table.active { display: table; }
.master-table th { background: rgba(15,23,42,0.9); color: var(--accent-blue); padding: 12px; text-align: left; font-weight: 600; border-bottom: 1px solid var(--border-color); }
.master-table td { padding: 12px; border-bottom: 1px solid rgba(255,255,255,0.05); color: var(--text-main); vertical-align: middle;}
.table-row-title { font-family: 'JetBrains Mono'; font-weight: bold; }

/* =========================================================
   PDF EXPORT OVERRIDES
   ========================================================= */
body.export-mode * {
    animation: none !important;
    transition: none !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
}
body.export-mode #engineering-drawer { background: rgba(17, 24, 39, 1) !important; }
body.export-mode h1 {
    background: none !important;
    -webkit-text-fill-color: var(--text-main) !important;
    color: var(--text-main) !important;
}