@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap');

:root {
    --background-color: #f0f2f5;
    --card-background: #ffffff;
    --primary-accent: #007aff;
    --primary-accent-hover: #005ecb;
    --text-primary: #1c1c1e;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --input-background: #f9fafb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --border-radius: 12px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    padding: 20px;
}

.app-container {
    width: 100%;
    max-width: 900px;
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.app-header {
    padding: 24px 32px;
    border-bottom: 1px solid var(--border-color);
}

.app-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.app-header p {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

.main-content {
    display: flex;
    flex-direction: column;
    padding: 24px 32px;
}

.qr-display-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 24px;
    background-color: var(--input-background);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    margin-bottom: 24px;
}

#qr-code-container {
    padding: 16px;
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
}

#qr-code canvas, #qr-code img {
    display: block;
}

#downloadBtn {
    width: 100%;
    max-width: 250px;
    text-align: center;
    padding: 12px;
    background-color: var(--primary-accent);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    transition: background-color 0.2s ease;
}

#downloadBtn:hover {
    background-color: var(--primary-accent-hover);
}

.controls-area {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

.control-group {
    display: flex;
    flex-direction: column;
}

.control-group label {
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-primary);
}

textarea, input[type="range"], select, .color-picker-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--input-background);
    font-size: 1rem;
    color: var(--text-primary);
}

textarea {
    min-height: 80px;
    resize: vertical;
}

.color-picker-group {
    display: flex;
    gap: 16px;
}

.color-picker-group > div {
    flex: 1;
}

.color-picker-group input[type="color"] {
    height: 44px;
    padding: 5px;
}

label[for="live-update-checkbox"] {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 400;
    cursor: pointer;
}

#generate-btn {
    padding: 12px;
    background-color: var(--primary-accent);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.hidden {
    display: none;
}

/* Responsive Design */
@media (min-width: 768px) {
    .main-content {
        flex-direction: row;
        gap: 32px;
    }

    .qr-display-area {
        flex: 0 0 300px; /* Do not grow, do not shrink, base width 300px */
        margin-bottom: 0;
    }

    .controls-area {
        flex: 1;
    }
}