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

:root {
    --black: #000000;
    --white: #ffffff;
    --gray-light: #f5f5f5;
    --gray-medium: #e0e0e0;
    --gray-dark: #666666;
    --gray-darker: #333333;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--black);
    background-color: var(--white);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* Header & Navigation */
header {
    background-color: var(--black);
    color: var(--white);
    padding: 1rem 0;
    border-bottom: 2px solid var(--white);
}

.navbar {
    width: 100%;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--white);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-menu a {
    color: var(--white);
    text-decoration: none;
    font-weight: 500;
    transition: opacity 0.3s;
    padding: 0.5rem 0;
}

.nav-menu a:hover,
.nav-menu a.active {
    opacity: 0.8;
    border-bottom: 2px solid var(--white);
}

/* Main Content */
main {
    flex: 1;
    padding: 3rem 0;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 4rem 0;
    border-bottom: 1px solid var(--gray-medium);
    margin-bottom: 3rem;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--black);
}

.hero p {
    font-size: 1.2rem;
    color: var(--gray-dark);
}

/* Blog Header */
.blog-header {
    text-align: center;
    padding: 2rem 0;
    border-bottom: 1px solid var(--gray-medium);
    margin-bottom: 3rem;
}

.blog-header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--black);
}

.blog-header p {
    font-size: 1.1rem;
    color: var(--gray-dark);
}

/* Posts Grid */
.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.posts-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Post Card */
.post-card-wrapper {
    position: relative;
}

.post-card {
    background-color: var(--white);
    border: 1px solid var(--gray-medium);
    padding: 2rem;
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
    text-decoration: none;
    color: var(--black);
    display: block;
}

.post-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    border-color: var(--black);
}

.post-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--black);
}

.post-card .post-meta {
    font-size: 0.9rem;
    color: var(--gray-dark);
    margin-bottom: 1rem;
    display: flex;
    gap: 1rem;
}

.post-card .post-excerpt {
    color: var(--gray-darker);
    line-height: 1.6;
    margin-top: 1rem;
}

/* Post Detail */
.post-detail {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    background-color: var(--white);
}

/* About Content */
.about-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    line-height: 1.8;
}

.about-content h1 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    color: var(--black);
    border-bottom: 2px solid var(--black);
    padding-bottom: 1rem;
}

.about-content h2 {
    font-size: 1.8rem;
    margin-top: 3rem;
    margin-bottom: 1.5rem;
    color: var(--black);
}

.about-content p {
    font-size: 1.1rem;
    color: var(--gray-darker);
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

.post-detail h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--black);
}

.post-detail .post-meta {
    font-size: 1rem;
    color: var(--gray-dark);
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--gray-medium);
    display: flex;
    gap: 1.5rem;
}

.post-detail .post-content {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--gray-darker);
    white-space: pre-wrap;
}

.post-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1rem;
}

.post-header h1 {
    flex: 1;
    margin: 0;
}

/* Delete Button */
.btn-delete {
    position: absolute;
    top: 1rem;
    right: 1rem;
    width: 30px;
    height: 30px;
    border: none;
    background-color: var(--black);
    color: var(--white);
    font-size: 1.5rem;
    line-height: 1;
    cursor: pointer;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    z-index: 10;
    padding: 0;
}

.btn-delete:hover {
    background-color: var(--gray-darker);
    transform: scale(1.1);
}

.btn-danger {
    background-color: var(--black);
    color: var(--white);
    border: 2px solid var(--black);
    padding: 0.5rem 1.5rem;
    font-size: 0.9rem;
}

.btn-danger:hover {
    background-color: var(--gray-darker);
    border-color: var(--gray-darker);
}

/* Login Section */
.login-section {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
    padding: 2rem 0;
}

.login-box {
    background-color: var(--white);
    border: 1px solid var(--gray-medium);
    padding: 3rem;
    max-width: 400px;
    width: 100%;
}

.login-box h1 {
    font-size: 2rem;
    margin-bottom: 2rem;
    text-align: center;
    color: var(--black);
}

.login-form {
    margin-top: 1rem;
}

.error-message {
    color: #d32f2f;
    background-color: #ffebee;
    padding: 0.75rem;
    margin-top: 1rem;
    border: 1px solid #ffcdd2;
    border-radius: 4px;
    text-align: center;
}

.logout-btn {
    cursor: pointer;
}

/* Write Section */
.write-section {
    max-width: 800px;
    margin: 0 auto;
}

.write-section h1 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--black);
}

.post-form {
    background-color: var(--white);
    padding: 2rem;
    border: 1px solid var(--gray-medium);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--black);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--gray-medium);
    font-size: 1rem;
    font-family: inherit;
    background-color: var(--white);
    color: var(--black);
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--black);
}

.form-group textarea {
    resize: vertical;
    min-height: 300px;
}

.form-actions {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.btn {
    padding: 0.75rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    border: 2px solid var(--black);
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
}

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

.btn-primary:hover {
    background-color: var(--gray-darker);
    border-color: var(--gray-darker);
}

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

.btn-secondary:hover {
    background-color: var(--gray-light);
}

/* Footer */
footer {
    background-color: var(--black);
    color: var(--white);
    padding: 2rem 0;
    margin-top: 3rem;
    border-top: 2px solid var(--white);
}

footer .container {
    text-align: center;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--gray-dark);
}

.empty-state h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--gray-darker);
}

.empty-state p {
    margin-bottom: 2rem;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        gap: 1rem;
        font-size: 0.9rem;
    }

    .hero h2 {
        font-size: 2rem;
    }

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

    .form-actions {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}