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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #ffffff;
    --bg-light: #f9fafb;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

header {
    background-color: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-bottom: 3rem;
}

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

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

main {
    flex: 1;
    padding-bottom: 3rem;
}

.essay-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.essay-card {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    color: inherit;
    display: block;
}

.essay-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.essay-card-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.essay-card-date {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
}

.essay-card-excerpt {
    color: var(--text-light);
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.essay-detail {
    max-width: 800px;
    margin: 0 auto;
}

.essay-detail.hidden {
    display: none;
}

.essay-grid.hidden {
    display: none;
}

.back-button {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
    margin-bottom: 2rem;
    transition: all 0.2s ease;
}

.back-button:hover {
    background-color: var(--bg-light);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.essay-content {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 3rem;
}

.essay-header {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.essay-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.essay-meta {
    color: var(--text-light);
    font-size: 1rem;
}

.essay-body {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--text-color);
}

.essay-body h1,
.essay-body h2,
.essay-body h3,
.essay-body h4 {
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-weight: 600;
    color: var(--text-color);
}

.essay-body h1 {
    font-size: 2rem;
}

.essay-body h2 {
    font-size: 1.75rem;
}

.essay-body h3 {
    font-size: 1.5rem;
}

.essay-body p {
    margin-bottom: 1.5rem;
}

.essay-body ul,
.essay-body ol {
    margin-bottom: 1.5rem;
    padding-left: 2rem;
}

.essay-body li {
    margin-bottom: 0.5rem;
}

.essay-body blockquote {
    border-left: 4px solid var(--primary-color);
    padding-left: 1.5rem;
    margin: 1.5rem 0;
    color: var(--text-light);
    font-style: italic;
}

.essay-body code {
    background-color: var(--bg-light);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: 'Monaco', 'Courier New', monospace;
    font-size: 0.9em;
}

.essay-body pre {
    background-color: var(--bg-light);
    padding: 1rem;
    border-radius: 6px;
    overflow-x: auto;
    margin: 1.5rem 0;
}

.essay-body pre code {
    background-color: transparent;
    padding: 0;
}

footer {
    background-color: var(--bg-color);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 3rem;
    text-align: center;
    color: var(--text-light);
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .essay-grid {
        grid-template-columns: 1fr;
    }

    .essay-content {
        padding: 2rem 1.5rem;
    }

    .essay-title {
        font-size: 2rem;
    }

    .essay-body {
        font-size: 1rem;
    }
}