:root {
    --bg: #f5efe4;
    --panel: rgba(255, 252, 245, 0.92);
    --panel-strong: rgba(255, 248, 234, 0.98);
    --ink: #1e2d24;
    --muted: #5d6d62;
    --line: rgba(50, 76, 61, 0.12);
    --accent: #1f7a5c;
    --accent-soft: #dff1e8;
    --secondary: #da6c2c;
    --danger: #c04b37;
    --sky: #3c7db6;
    --shadow: 0 22px 48px rgba(44, 54, 47, 0.12);
    --radius: 20px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Avenir Next", "Segoe UI", sans-serif;
    color: var(--ink);
    background:
        radial-gradient(circle at top left, rgba(31, 122, 92, 0.14), transparent 28%),
        radial-gradient(circle at top right, rgba(218, 108, 44, 0.16), transparent 24%),
        linear-gradient(180deg, #f9f4ea 0%, var(--bg) 100%);
}

.page-shell {
    max-width: 1500px;
    margin: 0 auto;
    padding: 28px 22px 36px;
}

.hero {
    padding: 28px 30px;
    margin-bottom: 22px;
    border-radius: 28px;
    background:
        linear-gradient(135deg, rgba(255, 255, 255, 0.82), rgba(245, 236, 218, 0.94)),
        linear-gradient(120deg, rgba(31, 122, 92, 0.12), rgba(218, 108, 44, 0.12));
    box-shadow: var(--shadow);
    border: 1px solid rgba(255, 255, 255, 0.7);
}

.hero h1 {
    margin: 0 0 10px;
    font-size: clamp(2rem, 3.2vw, 3.4rem);
    line-height: 1.06;
    letter-spacing: -0.03em;
}

.subtitle {
    margin: 0;
    max-width: 920px;
    color: var(--muted);
    font-size: 1.02rem;
    line-height: 1.7;
}

.layout {
    display: grid;
    grid-template-columns: 360px minmax(0, 1fr);
    gap: 22px;
}

.controls-column,
.viz-column {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.panel {
    padding: 18px;
    border-radius: var(--radius);
    background: var(--panel);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
    backdrop-filter: blur(16px);
}

.panel h2,
.panel h3 {
    margin: 0 0 14px;
    font-size: 1.04rem;
}

.eyebrow {
    margin: 0 0 6px;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    font-size: 0.72rem;
    color: var(--muted);
}

.control-group {
    margin-bottom: 14px;
}

.control-group:last-child {
    margin-bottom: 0;
}

.control-group label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 7px;
    color: var(--muted);
    font-size: 0.92rem;
}

.value-pill {
    padding: 4px 10px;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent);
    font-size: 0.82rem;
    font-weight: 700;
    white-space: nowrap;
}

select,
input[type="range"] {
    width: 100%;
}

select {
    padding: 11px 13px;
    border-radius: 14px;
    border: 1px solid var(--line);
    background: var(--panel-strong);
    color: var(--ink);
    font-size: 0.96rem;
}

input[type="range"] {
    appearance: none;
    height: 7px;
    border-radius: 999px;
    background: linear-gradient(90deg, rgba(31, 122, 92, 0.24), rgba(60, 125, 182, 0.32));
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid #fff;
    box-shadow: 0 6px 18px rgba(31, 122, 92, 0.28);
    cursor: pointer;
}

.button-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

button {
    border: none;
    border-radius: 14px;
    padding: 11px 12px;
    cursor: pointer;
    font-weight: 700;
    transition: transform 0.18s ease, opacity 0.18s ease, background 0.18s ease;
}

button:hover {
    transform: translateY(-1px);
}

.primary-btn {
    background: var(--accent);
    color: #fff;
}

.ghost-btn {
    background: rgba(31, 122, 92, 0.09);
    color: var(--accent);
}

.machine-controls {
    display: none;
}

.machine-controls.active {
    display: block;
}

.metric-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
}

.metric-card {
    padding: 12px;
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.58);
    border: 1px solid rgba(31, 122, 92, 0.08);
}

.metric-card strong {
    display: block;
    margin-top: 7px;
    font-size: 1.05rem;
}

.metric-label {
    font-size: 0.82rem;
    color: var(--muted);
}

.metric-card.highlight {
    background: linear-gradient(135deg, rgba(31, 122, 92, 0.12), rgba(31, 122, 92, 0.22));
}

.canvas-panel canvas {
    width: 100%;
    display: block;
    border-radius: 16px;
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(247, 240, 226, 0.96));
    border: 1px solid rgba(31, 122, 92, 0.08);
}

#machine-canvas {
    height: 420px;
}

#force-canvas,
#work-canvas {
    height: 270px;
}

.split-panels {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
}

.comparison-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px;
}

.comparison-card {
    padding: 14px;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.58);
    border: 1px solid rgba(31, 122, 92, 0.08);
}

.comparison-card.is-active {
    background: linear-gradient(135deg, rgba(31, 122, 92, 0.13), rgba(60, 125, 182, 0.12));
    border-color: rgba(31, 122, 92, 0.22);
}

.comparison-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
    font-size: 0.95rem;
}

.comparison-head strong {
    color: var(--accent);
}

.comparison-card p {
    margin: 6px 0 0;
    color: var(--muted);
}

.formula-list {
    display: grid;
    gap: 10px;
}

.formula-row {
    display: flex;
    justify-content: space-between;
    gap: 14px;
    padding: 11px 12px;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.56);
    border: 1px solid rgba(31, 122, 92, 0.08);
    align-items: center;
}

.formula-row span {
    color: var(--muted);
    font-size: 0.88rem;
}

.formula-row code {
    color: var(--ink);
    font-size: 0.86rem;
    text-align: right;
}

.explanation-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
    margin-top: 22px;
}

.explanation-grid p {
    margin: 0;
    color: var(--muted);
    line-height: 1.7;
    font-size: 0.94rem;
}

@media (max-width: 1180px) {
    .layout {
        grid-template-columns: 1fr;
    }

    .controls-column {
        order: 2;
    }

    .viz-column {
        order: 1;
    }

    .explanation-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 780px) {
    .page-shell {
        padding: 18px 14px 28px;
    }

    .split-panels,
    .comparison-grid,
    .explanation-grid,
    .metric-grid {
        grid-template-columns: 1fr;
    }

    .button-row {
        grid-template-columns: 1fr;
    }

    #machine-canvas {
        height: 340px;
    }
}