/* Material Sheet Generator - Cohesive Dark Theme */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700&display=swap');

:root {
    --bg-dark: #0a0a0a;
    --bg-panel: #161616;
    --accent: #3b82f6;
    --accent-glow: rgba(59, 130, 246, 0.5);
    --accent-hover: #2563eb;
    --text-main: #ffffff;
    --text-muted: #a1a1aa;
    --border: #27272a;
}

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

body {
    font-family: 'Inter', system-ui, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 20px;
    background-image: radial-gradient(circle at 50% 0%, #1a1a2e 0%, transparent 60%);
}

.container {
    max-width: 1000px;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

header {
    text-align: center;
    padding: 20px 0;
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(to bottom, #ffffff, #a0a0a0);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-muted);
    font-size: 1rem;
}

.back-link {
    display: inline-block;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    margin-bottom: 16px;
    transition: color 0.2s;
}

.back-link:hover {
    color: var(--text-main);
}

.controls {
    display: flex;
    justify-content: center;
    gap: 20px;
    align-items: center;
    background: var(--bg-panel);
    padding: 16px 24px;
    border-radius: 12px;
    border: 1px solid var(--border);
    flex-wrap: wrap;
}

.controls label {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-muted);
    font-size: 0.9rem;
}

select {
    background-color: var(--bg-dark);
    border: 1px solid var(--border);
    color: var(--text-main);
    padding: 8px 16px;
    border-radius: 8px;
    font-family: inherit;
    font-size: 0.9rem;
    cursor: pointer;
    transition: border-color 0.2s;
}

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

select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

button {
    background: var(--accent);
    color: white;
    padding: 10px 20px;
    border-radius: 8px;
    border: none;
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 4px 12px var(--accent-glow);
}

button:hover:not(:disabled) {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px var(--accent-glow);
}

button:disabled {
    background: var(--border);
    color: var(--text-muted);
    cursor: not-allowed;
    box-shadow: none;
}

.dropzone {
    border: 2px dashed var(--border);
    background-color: var(--bg-panel);
    border-radius: 12px;
    padding: 48px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
}

.dropzone p {
    color: var(--text-muted);
    font-size: 1rem;
}

.dropzone:hover,
.dropzone.dragover {
    border-color: var(--accent);
    background-color: rgba(59, 130, 246, 0.05);
}

#preview-container {
    background: var(--bg-panel);
    padding: 24px;
    border-radius: 12px;
    border: 1px solid var(--border);
    overflow: auto;
    display: flex;
    justify-content: center;
    /* Checkerboard pattern for transparency */
    background-image:
        linear-gradient(45deg, #1a1a1a 25%, transparent 25%),
        linear-gradient(-45deg, #1a1a1a 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #1a1a1a 75%),
        linear-gradient(-45deg, transparent 75%, #1a1a1a 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    background-color: #0d0d0d;
}

canvas {
    max-width: 100%;
    height: auto;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
    border-radius: 4px;
}

#file-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.file-tag {
    background: var(--bg-panel);
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.8rem;
    border: 1px solid var(--border);
    color: var(--text-muted);
}

/* RESPONSIVE DESIGN */
@media (max-width: 768px) {
    body {
        padding: 16px;
    }

    header h1 {
        font-size: 1.75rem;
    }

    header p {
        font-size: 0.95rem;
    }

    .controls {
        flex-direction: column;
        align-items: stretch;
        gap: 16px;
        padding: 20px;
    }

    .controls label {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    select,
    button {
        width: 100%;
    }

    .dropzone {
        padding: 36px 24px;
    }

    #preview-container {
        padding: 16px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 12px;
    }

    header {
        padding: 16px 0;
    }

    header h1 {
        font-size: 1.5rem;
    }

    header p {
        font-size: 0.9rem;
    }

    .container {
        gap: 20px;
    }

    .controls {
        padding: 16px;
        gap: 12px;
    }

    .dropzone {
        padding: 28px 20px;
    }

    .dropzone p {
        font-size: 0.9rem;
    }

    button {
        padding: 12px 20px;
    }
}