/* CSS Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 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);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius: 8px;
    --radius-lg: 12px;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
header {
    text-align: center;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

header .subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Controls Section */
.controls {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    display: grid;
    gap: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.control-group label span {
    color: var(--primary-color);
    font-weight: 700;
}

/* Select Styles */
select {
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: border-color 0.2s, box-shadow 0.2s;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    background-size: 1.25rem;
    padding-right: 2.5rem;
}

select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* Input Styles */
input[type="text"],
textarea {
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--text-primary);
    transition: border-color 0.2s, box-shadow 0.2s;
    font-family: inherit;
    resize: vertical;
}

input[type="text"]:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

input[type="text"]::placeholder,
textarea::placeholder {
    color: var(--text-secondary);
}

/* Range Slider Styles */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    outline: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
    box-shadow: var(--shadow-md);
}

input[type="range"]::-webkit-slider-thumb:hover {
    background: var(--primary-hover);
    transform: scale(1.1);
}

input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    transition: background-color 0.2s, transform 0.2s;
    box-shadow: var(--shadow-md);
}

input[type="range"]::-moz-range-thumb:hover {
    background: var(--primary-hover);
    transform: scale(1.1);
}

.weight-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--text-secondary);
    padding: 0 2px;
    margin-top: 0.25rem;
}

/* Preview Section */
.preview-section {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.preview-section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.preview-box {
    background: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius);
    padding: 2rem;
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow-wrap: break-word;
    word-break: break-word;
}

#preview-text {
    transition: font-family 0.3s, font-weight 0.3s, font-size 0.3s;
}

/* Compare Section */
.compare-section {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.compare-section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.compare-toggle {
    margin-bottom: 1rem;
}

.btn {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: white;
    background: var(--primary-color);
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn:active {
    transform: translateY(0);
}

.btn.active {
    background: var(--primary-hover);
}

.compare-grid {
    display: none;
    gap: 1rem;
}

.compare-grid.visible {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.weight-card {
    background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.25rem;
    transition: transform 0.2s, box-shadow 0.2s;
}

.weight-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.weight-card .weight-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.weight-card .weight-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.weight-card .weight-name {
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.weight-card .sample-text {
    font-size: 1.25rem;
    line-height: 1.5;
    color: var(--text-primary);
    overflow-wrap: break-word;
    word-break: break-word;
}

/* Footer Styles */
footer {
    text-align: center;
    padding: 2rem 0 1rem;
    margin-top: auto;
    border-top: 1px solid var(--border-color);
}

footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s;
}

footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Responsive Styles */
@media (min-width: 768px) {
    .container {
        padding: 3rem 2rem;
    }

    header h1 {
        font-size: 3rem;
    }

    .controls {
        grid-template-columns: repeat(2, 1fr);
        padding: 2rem;
    }

    .control-group:last-child {
        grid-column: 1 / -1;
    }

    .preview-box {
        padding: 3rem;
        min-height: 200px;
    }
}

@media (min-width: 1024px) {
    .controls {
        grid-template-columns: repeat(3, 1fr);
    }

    .control-group:nth-child(3),
    .control-group:nth-child(4) {
        grid-column: span 1;
    }

    .control-group:last-child {
        grid-column: 1 / -1;
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    header h1 {
        font-size: 1.75rem;
    }

    .controls,
    .preview-section,
    .compare-section {
        padding: 1rem;
    }

    .weight-labels {
        font-size: 0.65rem;
    }

    .compare-grid.visible {
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus visible for keyboard navigation */
:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000;
        --text-secondary: #000;
    }

    .preview-box,
    .weight-card {
        background: white;
        border-width: 2px;
    }
}