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

:root {
    --bg: #0f1117;
    --surface: #1a1d27;
    --border: #2a2d3a;
    --text: #e2e4ea;
    --text-muted: #8b8fa3;
    --accent: #6c63ff;
    --accent-hover: #7f78ff;
    --pixel-on: #e2e4ea;
    --pixel-off: #1a1d27;
    --grid-line: #252836;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family:
        "Segoe UI",
        system-ui,
        -apple-system,
        sans-serif;
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 860px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    font-size: 1.6rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.formula {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-family: "Cambria Math", "Latin Modern Math", serif;
}

h2 {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Grid Section */
.grid-section {
    margin-bottom: 1.5rem;
}

.grid-wrapper {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    overflow-x: auto;
    display: flex;
    justify-content: center;
}

#grid-canvas {
    cursor: crosshair;
    image-rendering: pixelated;
    display: block;
}

.grid-tools {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
}

/* Buttons */
button {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.15s ease;
    font-family: inherit;
}

button:hover {
    background: var(--border);
    border-color: var(--accent);
}

button:active {
    transform: scale(0.97);
}

#btn-self-ref {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

#btn-self-ref:hover {
    background: var(--accent-hover);
}

#btn-render-text,
#btn-render-k {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

#btn-render-text:hover,
#btn-render-k:hover {
    background: var(--accent-hover);
}

/* Text Section */
.text-section {
    margin-bottom: 1.5rem;
}

.text-controls {
    display: flex;
    gap: 0.75rem;
    align-items: center;
    flex-wrap: wrap;
}

.text-controls input[type="text"] {
    flex: 1;
    min-width: 160px;
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.5rem 0.75rem;
    font-size: 0.9rem;
    font-family: inherit;
    outline: none;
    transition: border-color 0.15s;
}

.text-controls input[type="text"]:focus {
    border-color: var(--accent);
}

.text-controls label {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--text-muted);
    font-size: 0.8rem;
    white-space: nowrap;
}

.text-controls input[type="range"] {
    width: 80px;
    accent-color: var(--accent);
}

#font-size-label {
    width: 30px;
    text-align: right;
}

/* K Section */
.k-section {
    margin-bottom: 2rem;
}

.k-controls textarea {
    width: 100%;
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.75rem;
    font-size: 0.8rem;
    font-family: "Consolas", "Fira Code", monospace;
    resize: vertical;
    outline: none;
    transition: border-color 0.15s;
    word-break: break-all;
}

.k-controls textarea:focus {
    border-color: var(--accent);
}

.k-buttons {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
}

/* Footer */
footer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--border);
    padding-top: 1.5rem;
}

/* Toast notification */
.toast {
    position: fixed;
    bottom: 1.5rem;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: var(--accent);
    color: #fff;
    padding: 0.5rem 1.25rem;
    border-radius: 6px;
    font-size: 0.85rem;
    opacity: 0;
    transition: all 0.3s ease;
    pointer-events: none;
    z-index: 100;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

@media (max-width: 600px) {
    .container {
        padding: 1rem;
    }

    h1 {
        font-size: 1.2rem;
    }

    .formula {
        font-size: 0.9rem;
    }

    .grid-wrapper {
        padding: 8px;
    }
}