:root {
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent-blue: #3b82f6;
    --accent-green: #10b981;
    --accent-orange: #f59e0b;
    --accent-red: #ef4444;
    --font: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { background-color: var(--bg-dark); color: var(--text-main); font-family: var(--font); line-height: 1.6; }
a { text-decoration: none; color: inherit; }

/* Header & Container Layouts */
header { display: flex; justify-content: space-between; align-items: center; padding: 1.5rem 5%; background: rgba(30, 41, 59, 0.7); backdrop-filter: blur(10px); position: sticky; top: 0; z-index: 100; border-bottom: 1px solid #334155; }
.logo { font-size: 1.5rem; font-weight: bold; color: var(--accent-blue); }
nav a { margin-left: 1.5rem; transition: color 0.3s; }
nav a:hover, nav a.active { color: var(--accent-blue); }
.container { max-width: 1200px; margin: 0 auto; padding: 2rem 5%; }

/* Grid Portfolio Cards */
.project-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 2rem; margin-top: 2rem; }
.card { background: var(--bg-card); border-radius: 12px; padding: 1.5rem; border: 1px solid #334155; transition: transform 0.3s, border-color 0.3s; display: flex; flex-direction: column; justify-content: space-between; }
.card:hover { transform: translateY(-5px); border-color: var(--accent-blue); }
.tag-container { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 1rem 0; }
.tag { font-size: 0.75rem; padding: 0.25rem 0.75rem; border-radius: 50px; background: #334155; font-weight: 600; }
.tag.industrial { color: var(--accent-orange); }
.tag.software { color: var(--accent-blue); }

/* Buttons & CTA Funnel Details */
.btn { display: inline-block; padding: 0.75rem 1.5rem; border-radius: 6px; font-weight: bold; cursor: pointer; text-align: center; border: none; transition: background 0.3s, transform 0.2s; }
.btn-primary { background: var(--accent-blue); color: #fff; }
.btn-primary:hover { background: #2563eb; }
.btn-outline { border: 2px solid var(--accent-blue); color: var(--accent-blue); background: transparent; }
.btn-outline:hover { background: var(--accent-blue); color: #fff; }

/* Detail Page Twin Layout Columns */
.detail-layout { display: grid; grid-template-columns: 2fr 1fr; gap: 2rem; margin-top: 2rem; }
@media (max-width: 900px) { .detail-layout { grid-template-columns: 1fr; } }

/* View Mode Toggles (Student/Client perspectives) */
.toggle-bar { display: flex; background: #334155; padding: 0.3rem; border-radius: 8px; margin-bottom: 1.5rem; max-width: fit-content; }
.toggle-btn { padding: 0.5rem 1.5rem; border-radius: 6px; border: none; background: transparent; color: var(--text-muted); cursor: pointer; font-weight: 600; }
.toggle-btn.active { background: var(--bg-dark); color: #fff; }

/* Interactive Sections styling placeholders */
.sandbox-box { background: #000; height: 400px; border-radius: 12px; display: flex; align-items: center; justify-content: center; color: var(--accent-green); font-family: monospace; border: 2px solid var(--bg-card); position: relative; }
.code-wrapper { background: #090d16; padding: 1.5rem; border-radius: 12px; overflow-x: auto; font-family: monospace; border: 1px solid #334155; color: #cbd5e1; font-size: 0.9rem; }

/* High-Converting Sticky Contextual Sidebar Form */
.sidebar-cta { background: var(--bg-card); border-radius: 12px; padding: 2rem; border: 1px solid #334155; position: sticky; top: 100px; height: fit-content; }
.form-group { margin-bottom: 1.25rem; }
.form-group label { display: block; font-size: 0.85rem; margin-bottom: 0.5rem; color: var(--text-muted); }
.form-group input, .form-group select, .form-group textarea { width: 100%; padding: 0.75rem; border-radius: 6px; border: 1px solid #334155; background: var(--bg-dark); color: #fff; }
.view-conditional { display: none; }
.view-conditional.active { display: block; }