/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --text-primary: #ffffff;
    --text-secondary: #e0e0e0;
    --bg-primary: #000000;
    --bg-secondary: #1a1a1a;
    --border-color: #404040;
    --accent-color: #00d4ff;
    --accent-hover: #00b8e6;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    --max-width: 800px;
    --border-radius: 8px;
    --transition: all 0.2s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
}

header {
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

h1 {
    font-size: 2.5rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

main {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

section {
    animation: fadeIn 0.5s ease-in;
}

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

h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

ul {
    list-style: none;
    padding-left: 0;
}

ul li {
    padding: var(--spacing-xs) 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: 1.5rem;
}

ul li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--text-primary);
    font-weight: 600;
}

.name-list li {
    font-size: 1.1rem;
    padding: var(--spacing-xs) 0;
}

/* Randomizer section */
.randomizer {
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.participant-checkboxes {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin: var(--spacing-sm) 0 var(--spacing-md) 0;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    padding: 0.5rem 1rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    transition: var(--transition);
    user-select: none;
}

.checkbox-label:hover {
    border-color: var(--accent-color);
    background: rgba(0, 212, 255, 0.1);
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent-color);
    margin: 0;
}

.checkbox-label input[type="checkbox"]:checked {
    accent-color: var(--accent-color);
}

.checkbox-label span {
    color: var(--text-primary);
    font-weight: 500;
}

.randomize-button {
    background-color: var(--accent-color);
    color: var(--bg-primary);
    border: none;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    margin-top: var(--spacing-sm);
    font-family: inherit;
}

.randomize-button:hover:not(:disabled) {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
}

.randomize-button:active:not(:disabled) {
    transform: translateY(0);
}

.randomize-button:disabled {
    background-color: var(--border-color);
    color: var(--text-secondary);
    cursor: not-allowed;
    opacity: 0.5;
}

.random-order {
    margin-top: var(--spacing-md);
    min-height: 60px;
}

.error-message {
    color: var(--accent-color);
    padding: var(--spacing-sm);
    text-align: center;
    font-weight: 500;
}

.random-order-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.random-order-list li {
    padding: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    animation: slideIn 0.3s ease-out;
    animation-fill-mode: both;
}

.random-order-list li::before {
    content: none;
}

.random-order-list li:nth-child(1) { animation-delay: 0.05s; }
.random-order-list li:nth-child(2) { animation-delay: 0.1s; }
.random-order-list li:nth-child(3) { animation-delay: 0.15s; }
.random-order-list li:nth-child(4) { animation-delay: 0.2s; }
.random-order-list li:nth-child(5) { animation-delay: 0.25s; }

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.order-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: var(--accent-color);
    color: var(--bg-primary);
    border-radius: 50%;
    font-size: 0.875rem;
    font-weight: 700;
    flex-shrink: 0;
}

.order-name {
    font-weight: 500;
    color: var(--text-primary);
}

/* Rules section */
.rules-list li {
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    border-left: 3px solid var(--accent-color);
    padding-left: var(--spacing-md);
}

.rules-list li::before {
    content: none;
}

.rules-list li strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.25rem;
    }

    main {
        gap: var(--spacing-md);
    }

    .randomizer {
        padding: var(--spacing-sm);
    }
}

/* Smooth transitions */
* {
    transition: var(--transition);
}