*,
*::before,
*::after {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Segoe UI", sans-serif;
    background: radial-gradient(circle at top, #111323 0%, #04040a 60%, #020208);
    color: #f5f7ff;
}

body {
    display: flex;
    justify-content: center;
    align-items: stretch;
}

/* Main layout */
#app {
    display: flex;
    flex-direction: row;
    width: 100%;
    max-width: 1400px;
    height: 100vh;
    padding: 16px;
    gap: 16px;
}

/* Visual panel (canvas) */
.visual-panel {
    flex: 1.35;
    background: radial-gradient(circle at center, #1b1f39, #050612 70%);
    border-radius: 24px;
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.75);
    position: relative;
    padding: 12px;
    display: flex;
    flex-direction: column;
}

#chladniCanvas {
    flex: 1;
    border-radius: 18px;
    background: #05060b;
    display: block;
}

/* Mode info overlay */
.mode-info {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    padding-top: 8px;
    color: #c3c8ff;
}

.mode-info span {
    opacity: 0.9;
}

/* Control panel (sidebar) */
.control-panel {
    flex: 1;
    background: rgba(7, 10, 28, 0.96);
    border-radius: 24px;
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.65);
    padding: 20px 22px;
    overflow-y: auto;
}

.control-panel h1 {
    font-size: 1.7rem;
    margin: 0 0 12px;
    letter-spacing: 0.03em;
}

.controls {
    border-bottom: 1px solid rgba(200, 204, 255, 0.2);
    padding-bottom: 14px;
    margin-bottom: 14px;
}

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

.control-group h2 {
    font-size: 1.05rem;
    margin: 10px 0;
}

label {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 4px;
    font-size: 0.9rem;
}

.value-label {
    font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Monaco,
    Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.85rem;
    color: #9dd6ff;
}

/* Inputs */
input[type="range"] {
    width: 100%;
    accent-color: #6cc6ff;
}

select {
    width: 100%;
    padding: 6px 8px;
    border-radius: 999px;
    border: 1px solid rgba(180, 190, 255, 0.4);
    background: rgba(5, 11, 30, 0.8);
    color: #f3f4ff;
    font-size: 0.9rem;
}

/* Explanation text */
.explanation h2,
.explanation h3 {
    margin-top: 12px;
    margin-bottom: 6px;
    font-size: 1rem;
}

.explanation p {
    font-size: 0.88rem;
    line-height: 1.45;
    margin: 4px 0;
    color: #dde0ff;
}

.explanation ul {
    padding-left: 20px;
    margin: 6px 0;
}

.explanation li {
    font-size: 0.88rem;
    margin-bottom: 3px;
}

/* Math formulas block */
.formula {
    text-align: center;
}

/* Utility */
.hidden {
    display: none;
}

/* Responsive */
@media (max-width: 1000px) {
    #app {
        flex-direction: column;
    }

    .control-panel {
        max-height: 45vh;
    }
}