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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --success-color: #22c55e;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-hover: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
    --radius: 12px;
    --radius-sm: 8px;
}

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

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

/* Container */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

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

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* Cards */
.card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.card h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.card .description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* UUID Display */
.uuid-display {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.uuid-display input {
    flex: 1;
    padding: 0.75rem 1rem;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 1rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    outline: none;
    transition: border-color 0.2s;
}

.uuid-display input:focus {
    border-color: var(--primary-color);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s;
    outline: none;
}

.btn:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

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

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

.btn-copy {
    padding: 0.75rem;
    background: var(--surface-hover);
    color: var(--text-secondary);
    min-width: 44px;
}

.btn-copy:hover {
    background: var(--primary-color);
    color: white;
}

.btn-copy svg {
    flex-shrink: 0;
}

/* Bulk Generation */
.bulk-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.bulk-controls label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.bulk-controls input[type="number"] {
    width: 100px;
    padding: 0.5rem 0.75rem;
    font-size: 1rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    outline: none;
}

.bulk-controls input[type="number"]:focus {
    border-color: var(--primary-color);
}

.bulk-output-container {
    margin-top: 1rem;
    position: relative;
}

#bulk-output {
    width: 100%;
    min-height: 150px;
    padding: 1rem;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.9rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    resize: vertical;
    outline: none;
}

#bulk-output:focus {
    border-color: var(--primary-color);
}

.btn-copy-bulk {
    margin-top: 0.75rem;
}

/* Validator */
.validator-input {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.validator-input input {
    flex: 1;
    padding: 0.75rem 1rem;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 1rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    outline: none;
    transition: border-color 0.2s;
}

.validator-input input:focus {
    border-color: var(--primary-color);
}

.validation-result {
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    display: none;
}

.validation-result.valid {
    display: block;
    background: rgba(34, 197, 94, 0.15);
    border: 1px solid var(--success-color);
    color: var(--success-color);
}

.validation-result.invalid {
    display: block;
    background: rgba(239, 68, 68, 0.15);
    border: 1px solid var(--error-color);
    color: var(--error-color);
}

.validation-result .uuid-info {
    margin-top: 0.5rem;
    font-size: 0.85rem;
    opacity: 0.9;
}

/* Footer */
footer {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

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

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--surface);
    color: var(--text-primary);
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

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

.toast.success {
    border-color: var(--success-color);
}

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

    header h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .card {
        padding: 1.25rem;
    }

    .uuid-display {
        flex-direction: column;
    }

    .uuid-display input {
        font-size: 0.9rem;
    }

    .btn-copy {
        width: 100%;
    }

    .bulk-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .bulk-controls input[type="number"] {
        width: 100%;
    }

    .validator-input {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}

@media (max-width: 400px) {
    header h1 {
        font-size: 1.75rem;
    }

    .card h2 {
        font-size: 1.1rem;
    }

    .uuid-display input,
    .validator-input input {
        font-size: 0.85rem;
        padding: 0.6rem 0.8rem;
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card {
    animation: fadeIn 0.3s ease forwards;
}

.card:nth-child(2) {
    animation-delay: 0.1s;
}

.card:nth-child(3) {
    animation-delay: 0.2s;
}

.card:nth-child(4) {
    animation-delay: 0.3s;
}

/* Selection */
::selection {
    background: var(--primary-color);
    color: white;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}