:root {
    --bg-color: #0b0d14;
    --text-color: #ffffff;
    --glass-bg: rgba(16, 20, 32, 0.70);
    --glass-border: rgba(255, 255, 255, 0.08);
    --accent: #22d3ee; /* Cyan for capacitor */
    --accent-glow: rgba(34, 211, 238, 0.3);
    --accent-hover: #67e8f9;
    
    --secondary-bg: rgba(255, 255, 255, 0.05);
    --secondary-hover: rgba(255, 255, 255, 0.1);
    
    --danger: #ef4444;
    --danger-hover: #f87171;
    
    /* Result Highlights */
    --color-cyan: #22d3ee;
    --color-pink: #ec4899;
    --color-yellow: #fde047;
    --color-green: #34d399;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Inter', sans-serif;
    background:
        radial-gradient(circle at 10% 20%, rgba(34, 211, 238, 0.08), transparent 45%),
        radial-gradient(circle at 90% 80%, rgba(236, 72, 153, 0.08), transparent 45%),
        var(--bg-color);
    background-size: 200% 200%;
    animation: backgroundShift 15s ease infinite;
    color: var(--text-color);
    overflow: hidden;
    width: 100vw;
    height: 100vh;
    height: -webkit-fill-available;
}

@keyframes backgroundShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

#capacitorCanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    touch-action: none;
}

/* === Glassmorphism Basics === */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.45);
    z-index: 10;
}

.glass-panel-small {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    padding: 1rem;
    z-index: 10;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.hidden { display: none !important; }

/* === Typography & Utilities === */
h1 { font-size: 1.2rem; font-weight: 600; letter-spacing: -0.5px; }
h3 { font-size: 0.9rem; font-weight: 600; color: #cbd5e1; margin-bottom: 0.8rem; text-transform: uppercase; letter-spacing: 0.5px; }
.w-full { width: 100%; }
.mt-2 { margin-top: 0.5rem; }
.mb-2 { margin-bottom: 0.5rem; }
.color-cyan { color: var(--color-cyan); }
.color-pink { color: var(--color-pink); }
.color-yellow { color: var(--color-yellow); }
.color-green { color: var(--color-green); }

/* === Top Nav === */
.top-nav {
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1.5rem;
    border-radius: 0 0 16px 16px;
    border-top: none;
}

.nav-left, .nav-center, .nav-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-center { flex: 1; justify-content: center; }

/* Buttons */
button {
    font-family: 'Inter', sans-serif;
    cursor: pointer;
    border: none;
    outline: none;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent), var(--accent-hover));
    color: #000;
    padding: 0.5rem 1.4rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.95rem;
    box-shadow: 0 4px 15px var(--accent-glow);
}
.btn-primary:hover { transform: translateY(-2px) scale(1.02); }

.btn-secondary {
    background: var(--secondary-bg);
    color: white;
    border: 1px solid var(--glass-border);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-weight: 500;
    font-size: 0.9rem;
}
.btn-secondary:hover { background: var(--secondary-hover); }

.btn-danger {
    background: rgba(239, 68, 68, 0.1); color: #fca5a5;
    border: 1px solid rgba(239, 68, 68, 0.3);
    padding: 0.5rem 1rem; border-radius: 8px;
    font-weight: 500; font-size: 0.9rem;
}
.btn-danger:hover { background: rgba(239, 68, 68, 0.2); color: white; border-color: var(--danger-hover); }

.btn-icon {
    width: 36px; height: 36px;
    border-radius: 8px; background: var(--secondary-bg);
    border: 1px solid var(--glass-border);
    color: white; font-size: 1.1rem; text-decoration: none;
}
.btn-icon:hover { background: var(--secondary-hover); }
.home-btn { font-size: 1.3rem; }

.divider { height: 24px; width: 1px; background: var(--glass-border); margin: 0 0.5rem; }

/* === Sidebars === */
.sidebar-left {
    position: absolute;
    top: 76px; bottom: 16px;
    left: 16px; width: 300px;
    border-radius: 16px;
    padding: 1.2rem;
    display: flex; flex-direction: column; overflow-y: auto;
}

.sidebar-left::-webkit-scrollbar { width: 4px; }
.sidebar-left::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.2); border-radius: 4px; }

/* Form Controls */
.prop-group { display: flex; flex-direction: column; margin-bottom: 0.8rem; }
.prop-group label { font-size: 0.8rem; color: #cbd5e1; margin-bottom: 0.4rem; }

.custom-select { position: relative; }
.custom-select select {
    appearance: none; -webkit-appearance: none;
    width: 100%; background: rgba(0,0,0,0.3); border: 1px solid rgba(255,255,255,0.1);
    color: white; padding: 0.6rem 0.8rem; border-radius: 6px;
    font-family: inherit; font-size: 0.9rem; outline: none; cursor:pointer;
}

.prop-input-wrap { display: flex; align-items: center; }
.slider-wrap {
    background: rgba(0,0,0,0.3);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 6px;
    padding: 0 0.8rem; display: flex; align-items: center;
}
.slider-wrap input[type="range"] {
    appearance: none; -webkit-appearance: none; width: 100%; height: 4px; border-radius: 2px;
    background: rgba(255,255,255,0.2); outline: none; margin-right: 1rem;
}
.slider-wrap input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none; width: 14px; height: 14px; border-radius: 50%;
    background: var(--accent); cursor: pointer; transition: transform 0.1s;
}
.slider-wrap input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.3); }

.val-readout {
    font-family: 'SF Mono', monospace;
    font-size: 0.85rem; color: #cbd5e1;
    min-width: 50px; text-align: right;
}

/* === Bottom Info Panels === */
.bottom-left { position: absolute; bottom: 16px; left: 332px; width: 240px; }
.bottom-right { position: absolute; bottom: 16px; right: 16px; width: 220px; }

.reading { font-size: 0.8rem; color: #cbd5e1; margin-bottom: 0.4rem; font-family: 'SF Mono', monospace; display:flex; justify-content:space-between; }
.reading strong { color: #f8fafc; font-family: 'Inter', sans-serif; font-weight: 500; }
.reading span { font-weight: 600; text-shadow: 0 0 10px rgba(255,255,255,0.1); }

/* Toggles */
.toggle-row {
    display: flex; align-items: center; justify-content: space-between;
    padding: 0.35rem 0; cursor: pointer; font-size: 0.82rem; color: #cbd5e1;
}
.toggle-row input[type="checkbox"] { display: none; }
.toggle-switch {
    position: relative; width: 32px; height: 18px;
    background: rgba(255,255,255,0.1); border-radius: 9px; transition: background 0.25s ease;
}
.toggle-switch::after {
    content: ''; position: absolute; top: 2px; left: 2px;
    width: 14px; height: 14px; border-radius: 50%;
    background: rgba(255,255,255,0.4); transition: all 0.25s ease;
}
input[type="checkbox"]:checked + .toggle-switch { background: var(--accent); }
input[type="checkbox"]:checked + .toggle-switch::after { left: 16px; background: #000; }

.zoom-controls { display: flex; align-items: center; justify-content: space-between; margin-top: 0.8rem; padding-top: 0.8rem; border-top: 1px solid var(--glass-border); }
#zoomLabel { font-size: 0.8rem; font-family: 'SF Mono', monospace; color: #94a3b8; width: 50px; text-align: center; }


/* Modal */
.modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.8); backdrop-filter: blur(5px);
    display: flex; justify-content: center; align-items: center; z-index: 1000;
}
.modal-content {
    background: var(--bg-color); width: 90%; max-width: 600px;
    border-radius: 16px; padding: 2rem;
}
.formula-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.formula-card {
    background: rgba(255,255,255,0.03); padding: 1rem; border-radius: 8px;
    border: 1px solid rgba(255,255,255,0.05); text-align: center;
}
.formula-card h4 { color: #94a3b8; font-size: 0.9rem; margin-bottom: 0.5rem; text-transform: uppercase;}
.formula-card p { font-size: 0.9rem; margin-bottom: 0.3rem;}


/* === Network Tree List === */
.network-tree-list {
    max-height: 200px;
    overflow-y: auto;
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: 8px;
    background: rgba(0,0,0,0.25);
    margin-bottom: 0.6rem;
}
.network-tree-list::-webkit-scrollbar { width: 3px; }
.network-tree-list::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.15); border-radius: 3px; }

.net-node-item {
    padding: 0.35rem 0.5rem;
    font-size: 0.78rem;
    font-family: 'SF Mono', monospace;
    color: #cbd5e1;
    cursor: pointer;
    border-bottom: 1px solid rgba(255,255,255,0.03);
    transition: all 0.15s ease;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}
.net-node-item:hover {
    background: rgba(255,255,255,0.06);
    color: #e2e8f0;
}
.net-node-item.selected {
    background: rgba(34, 211, 238, 0.12);
    color: #22d3ee;
    border-left: 3px solid #22d3ee;
}
.net-node-item.cap-node .node-icon { color: #ec4899; }
.net-node-item.series-group { color: #67e8f9; }
.net-node-item.series-group .node-icon { color: #22d3ee; }
.net-node-item.parallel-group { color: #f9a8d4; }
.net-node-item.parallel-group .node-icon { color: #ec4899; }
.node-icon { font-size: 0.9rem; flex-shrink: 0; }


/* ========== RESPONSIVE: MOBILE ========== */
@media (max-width: 768px) {
    .top-nav { 
        height: auto; 
        padding: 0.4rem 0.5rem; 
        flex-wrap: nowrap; 
        gap: 0.3rem; 
        border-radius: 0; 
    }
    h1 { font-size: 0.9rem; }
    .title-group { display: none; }
    .divider { display: none; }
    .nav-left { gap: 0.5rem; flex-shrink: 0; }
    .nav-center { flex: 1; justify-content: center; gap: 0.3rem; }
    .btn-primary, .btn-secondary { 
        padding: 0.4rem 0.7rem; 
        font-size: 0.78rem; 
        min-height: 36px; 
    }
    .btn-icon { width: 36px; height: 36px; min-width: 36px; }
    
    /* Sidebars at bottom as pull-up panel */
    .sidebar-left {
        position: fixed; 
        top: auto; 
        bottom: 0; 
        left: 0; 
        width: 100%;
        height: auto; 
        max-height: 50vh; 
        border-radius: 16px 16px 0 0; 
        z-index: 20; 
        padding: 0.8rem;
    }
    
    .network-tree-list {
        max-height: none;
        overflow-y: visible;
    }
    
    /* HUD panels - positioned above the sidebar */
    .bottom-left {
        position: fixed;
        bottom: auto;
        top: 55px;
        left: 8px;
        width: auto;
        max-width: 180px;
        padding: 0.6rem;
        font-size: 0.7rem;
        z-index: 15;
    }
    .bottom-left h3 { font-size: 0.7rem; margin-bottom: 0.4rem; }
    .bottom-left .reading { font-size: 0.65rem; margin-bottom: 0.2rem; }
    .bottom-left .reading strong { font-size: 0.65rem; }
    
    /* View controls - top right on mobile */
    .bottom-right { 
        position: fixed;
        bottom: auto;
        top: 55px;
        right: 8px;
        width: auto;
        max-width: 160px;
        padding: 0.5rem;
        z-index: 15;
    }
    .bottom-right .toggle-row { font-size: 0.7rem; padding: 0.2rem 0; }
    .bottom-right .toggle-switch { width: 28px; height: 16px; }
    .bottom-right .toggle-switch::after { width: 12px; height: 12px; }
    .bottom-right input[type="checkbox"]:checked + .toggle-switch::after { left: 14px; }
    .zoom-controls { margin-top: 0.5rem; padding-top: 0.5rem; }
    #zoomLabel { font-size: 0.7rem; }
    
    /* Prop group and slider tweaks for mobile */
    .prop-group label { font-size: 0.75rem; }
    .val-readout { font-size: 0.75rem; min-width: 40px; }
    .slider-wrap { padding: 0 0.5rem; }
    .slider-wrap input[type="range"]::-webkit-slider-thumb {
        width: 20px; height: 20px;
    }
    
    /* Network sidebar specifics */
    .btn-group .btn-primary, .btn-group .btn-secondary {
        padding: 0.5rem;
        font-size: 0.8rem;
    }
    
    /* Modal responsive */
    .modal-content {
        width: 95%;
        max-width: none;
        padding: 1.2rem;
    }
    .formula-grid { 
        grid-template-columns: 1fr; 
        gap: 0.6rem; 
    }
}

@media (max-width: 380px) {
    .top-nav { padding: 0.3rem; }
    .btn-primary, .btn-secondary { 
        padding: 0.3rem 0.5rem; 
        font-size: 0.7rem; 
    }
    .sidebar-left { max-height: 30vh; padding: 0.5rem; }
    .bottom-left { max-width: 150px; }
    .bottom-right { max-width: 130px; }
}