:root {
    /* Brand Design Tokens */
    --bg-color: #FFFFFF;
    --text-primary: #09090B;
    --text-secondary: #71717A;
    /* Muted equivalent */
    --card-bg: #FFFFFF;
    --border-color: #E4E4E7;
    /* Light gray border */

    --font-heading: 'Inter', sans-serif;
    --font-body: 'Roboto', sans-serif;

    --radius: 0.5rem;
    /* 8px */

    /* LeetCode Specifics - kept for context */
    --accent: #ffa116;
    --easy: #00b8a3;
    --medium: #ffc01e;
    --hard: #ff375f;
}

body {
    margin: 0;
    font-family: var(--font-body);
    background: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    padding: 2rem;
    width: 100%;
    max-width: 480px;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 2.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

.hidden {
    display: none;
}

.loading,
.error {
    text-align: center;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.avatar {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    /* Brand didn't specify, but round is standard */
    border: 2px solid var(--border-color);
}

.user-info h1 {
    font-family: var(--font-heading);
    margin: 0;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.subtitle {
    margin: 0.25rem 0 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.rank-container {
    text-align: center;
    margin-bottom: 2.5rem;
}

.label {
    display: block;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    font-family: var(--font-heading);
    margin-bottom: 0.5rem;
}

.rank-value {
    font-family: var(--font-heading);
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-top: 2rem;
}

.stat-item {
    text-align: center;
    background: #F4F4F5;
    /* Secondary background from tokens */
    padding: 1rem;
    border-radius: var(--radius);
}

.stat-count {
    display: block;
    font-size: 1.25rem;
    font-weight: 700;
    font-family: var(--font-heading);
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.025em;
}

.easy {
    color: var(--easy);
}

.medium {
    color: var(--medium);
}

.hard {
    color: var(--hard);
}

.footer {
    margin-top: 2rem;
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(5px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#content {
    animation: fadeIn 0.4s ease-out;
}

.chart-container {
    margin-top: 2.5rem;
    position: relative;
    height: 300px;
    width: 100%;
}