:root {
    --bg-color: #0f172a;
    --text-color: #e2e8f0;
    --accent-color: #38bdf8;
    --accent-glow: rgba(56, 189, 248, 0.5);
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --font-main: 'Outfit', sans-serif;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.container {
    width: 100%;
    max-width: 800px;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

header {
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 600;
    background: linear-gradient(135deg, #fff, var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 20px var(--accent-glow);
    margin-bottom: 0.5rem;
}

header p {
    font-weight: 300;
    opacity: 0.8;
}

.simulation-container {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 1rem;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
}

canvas {
    display: block;
    width: 100%;
    height: 600px; /* Base height, scaled by JS */
    border-radius: 12px;
}

.controls {
    width: 100%;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    margin-top: 1rem;
    padding: 1rem;
    gap: 1.5rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 12px;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 10px;
    background: rgba(255, 255, 255, 0.03);
    padding: 0.3rem 0.8rem;
    border-radius: 8px;
}

.control-group label {
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.9;
    white-space: nowrap;
    font-weight: 500;
}

input[type=range] {
    -webkit-appearance: none;
    appearance: none;
    width: 120px;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 5px;
    outline: none;
}

input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent-color);
    cursor: pointer;
    box-shadow: 0 0 10px var(--accent-glow);
    transition: transform 0.2s;
}

input[type=range]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    color: var(--text-color);
    padding: 0.6rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-family: var(--font-main);
    font-weight: 600;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn:hover {
    background: var(--accent-color);
    color: #000;
    box-shadow: 0 0 15px var(--accent-glow);
}

select {
    background: rgba(40, 50, 70, 0.6);
    border: 1px solid var(--glass-border);
    color: var(--text-color);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-family: var(--font-main);
    font-size: 0.9rem;
    outline: none;
    cursor: pointer;
    transition: all 0.2s;
}

select:hover {
    background: rgba(60, 70, 90, 0.8);
    border-color: var(--accent-color);
}

select option {
    background: var(--bg-color);
    color: var(--text-color);
}

.stat-overlay {
    position: absolute;
    top: 20px;
    right: 20px;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    padding: 0.5rem 1rem;
    border-radius: 12px;
    display: flex;
    gap: 0.5rem;
    align-items: center;
    font-size: 1.1rem;
    color: var(--text-color);
    z-index: 10;
    pointer-events: none;
}

.stat-overlay .value {
    color: var(--accent-color);
    font-weight: 600;
    text-shadow: 0 0 10px var(--accent-glow);
}

/* Unified Input Group */
.input-group-merged {
    display: flex;
    align-items: center;
    background: rgba(40, 50, 70, 0.6);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 0;
    margin-top: 5px;
    overflow: hidden;
    width: 100px;
}

.input-group-merged input {
    background: transparent;
    border: none;
    color: var(--text-color);
    padding: 0.4rem 0.5rem;
    width: 60%;
    font-family: var(--font-main);
    font-size: 0.9rem;
    outline: none;
    text-align: center;
}

.input-group-merged span {
    background: rgba(255,255,255,0.05);
    color: rgba(255,255,255,0.6);
    padding: 0.4rem 0.5rem;
    width: 40%;
    font-size: 0.8rem;
    text-align: center;
    border-left: 1px solid var(--glass-border);
    white-space: nowrap;
}

/* Remove arrows from number input */
.input-group-merged input::-webkit-outer-spin-button,
.input-group-merged input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Row Controls */
.row-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.small-btn {
    width: 32px;
    height: 32px;
    padding: 0;
    font-size: 1.2rem;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.value-display {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent-color);
    text-shadow: 0 0 5px var(--accent-glow);
    min-width: 30px;
    text-align: center;
}