h1 {
    text-align: center;
    font-size: 2rem;
    color: var(--primary-color, #1e293b);
    margin-bottom: 25px;
    font-weight: 800;
}

.description {
    margin-bottom: 30px;
    color: #64748b;
    font-size: 1.05rem;
    text-align: center;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}
:root {
    --primary-color: #1e293b;
    --accent-color: #3b82f6;
    --bg-color: #f1f5f9;
    --panel-bg: #ffffff;
    --text-color: #334155;
    --border-color: #e2e8f0;
}

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

body {
    font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container { margin: 20px; }

.card {
    background: #ffffff;
    border-radius: 20px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
    padding: 40px;
    border: 1px solid var(--border-color);
    position: relative;
}

h1 {
    text-align: center;
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 25px;
    font-weight: 800;
}

.description {
    margin-bottom: 30px;
    color: #64748b;
    font-size: 1.05rem;
    text-align: center;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.sim-wrapper {
    justify-content: center;
    margin: 30px 0;
    overflow: visible;
}

#total {
    width: 880px;
    height: 520px;
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    position: relative;
    box-shadow: 0 4px 12px rgba(0,0,0,0.03);
    overflow: hidden;
    flex-shrink: 0;
    transform-origin: center center;
}

#canvas {
    position: absolute;
    left: 0;
    top: 0;
    width: 600px;
    height: 520px;
}

#panel {
    position: absolute;
    padding: 15px;
    left: 600px;
    top: 0;
    width: 280px;
    height: 520px;
    background: #f8fafc;
    border-left: 1px solid var(--border-color);
    font-size: 0.85rem;
    flex-direction: column;
}

.btn-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
}

.btn-logic {
    padding: 8px;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
    background: #fff;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.2s;
}

.btn-logic:hover {
    background: #f1f5f9;
    border-color: #94a3b8;
}

.btn-clear { background-color: #ecfeff; }
.btn-reset { background-color: #fefce8; }
.btn-op { background-color: #f1f5f9; font-size: 1.1rem; }

.input-row {
    justify-content: space-between;
    align-items: center;
    padding: 4px 0;
}

select {
    padding: 4px;
    border-radius: 4px;
    border: 1px solid #cbd5e1;
    width: 80px;
}

.footer-info {
    text-align: center;
    margin-top: 40px;
    font-size: 0.85rem;
    color: #94a3b8;
}

@media (max-width: 850px) {
    #total { /* scale removed */ }
    .sim-wrapper { height: 380px; align-items: center; }
}
@media (max-width: 750px) {
    #total { /* scale removed */ }
    .sim-wrapper { height: 340px; }
}
@media (max-width: 650px) {
    #total { /* scale removed */ }
    .sim-wrapper { height: 280px; }
    .card { padding: 30px 20px; }
}
@media (max-width: 500px) {
    #total { /* scale removed */ }
    .sim-wrapper { height: 220px; }
    h1 { font-size: 1.5rem; }
}