/* ==================== CSS Variables ==================== */
:root {
    --primary-bg: #ffffff;
    --secondary-bg: #f5f5f7;
    --tertiary-bg: #efefef;
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --text-tertiary: #a1a1a6;
    --border-color: #e5e5e7;
    --accent-color: #0071e3;
    --accent-hover: #0077ed;
    --danger-color: #ff3b30;
    --success-color: #34c759;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.16);
}

/* ==================== Global Styles ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', sans-serif;
    background-color: var(--primary-bg);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ==================== Header & Navigation ==================== */
.header {
    background-color: var(--primary-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(20px);
    background-color: rgba(255, 255, 255, 0.95);
}

.navbar {
    padding: 0.75rem 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 2rem;
}

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

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.2s ease;
    cursor: pointer;
}

.nav-link:hover {
    color: var(--text-primary);
}

.auth-btn {
    padding: 0.5rem 1rem;
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.auth-btn:hover {
    background-color: var(--accent-hover);
}

.auth-btn.logged {
    background-color: var(--success-color);
}

/* ==================== Main Container ==================== */
.main-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 4rem 0;
}

/* ==================== Home Section ==================== */
.home-section {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
}

.hero-content {
    text-align: center;
    animation: fadeInUp 0.8s ease;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    letter-spacing: -1px;
    line-height: 1.1;
}

.hero-content p {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.cta-btn {
    padding: 0.75rem 2rem;
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.cta-btn:hover {
    background-color: var(--accent-hover);
    box-shadow: var(--shadow-md);
}

.cta-btn:active {
    transform: scale(0.98);
}

/* ==================== Articles Section ==================== */
.articles-section {
    padding: 3rem 0;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.section-header h2 {
    font-size: 2rem;
    font-weight: 600;
    letter-spacing: -0.5px;
}

.publish-btn {
    padding: 0.6rem 1.2rem;
    background-color: var(--secondary-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

.publish-btn:hover {
    background-color: var(--tertiary-bg);
    border-color: var(--text-tertiary);
}

.articles-container {
    display: grid;
    gap: 1.5rem;
}

.loading {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

.article-card {
    padding: 1.5rem;
    background-color: var(--primary-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    transition: all 0.2s ease;
    cursor: pointer;
}

.article-card:hover {
    border-color: var(--accent-color);
    box-shadow: var(--shadow-sm);
    transform: translateY(-2px);
}

.article-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-tertiary);
}

.article-date {
    display: flex;
    align-items: center;
}

.article-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: var(--secondary-bg);
    color: var(--text-secondary);
    border-radius: 4px;
    font-size: 0.8rem;
}

.article-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.article-excerpt {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.article-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.read-more {
    color: var(--accent-color);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
}

.read-more:hover {
    color: var(--accent-hover);
}

.article-author {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-tertiary);
}

/* ==================== About Section ==================== */
.about-section {
    padding: 4rem 0;
}

.about-section h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 2rem;
}

.about-content {
    max-width: 800px;
}

.about-content p {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

/* ==================== Modal Styles ==================== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.4);
    z-index: 2000;
    animation: fadeIn 0.2s ease;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: var(--primary-bg);
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    animation: slideUp 0.3s ease;
}

.detail-modal-content {
    max-width: 800px;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.3rem;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color 0.2s ease;
    line-height: 1;
    padding: 0;
    width: 2rem;
    height: 2rem;
}

.modal-close:hover {
    color: var(--text-primary);
}

/* ==================== Form Styles ==================== */
.publish-form {
    padding: 1.5rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 0.95rem;
    color: var(--text-primary);
    transition: border-color 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(0, 113, 227, 0.1);
}

.form-group textarea {
    resize: vertical;
    font-family: -apple-system, BlinkMacSystemFont, 'Menlo', monospace;
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    padding-top: 1rem;
}

.btn-cancel,
.btn-publish {
    padding: 0.6rem 1.2rem;
    border: none;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-cancel {
    background-color: var(--secondary-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-cancel:hover {
    background-color: var(--tertiary-bg);
}

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

.btn-publish:hover {
    background-color: var(--accent-hover);
}

.btn-publish:active {
    transform: scale(0.98);
}

/* ==================== Article Detail ==================== */
.article-detail {
    padding: 2rem;
}

.detail-title {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.detail-meta {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.9rem;
    color: var(--text-secondary);
    flex-wrap: wrap;
}

.detail-meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.detail-body {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.8;
    word-break: break-word;
}

.detail-body h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 2rem 0 1rem 0;
    color: var(--text-primary);
}

.detail-body h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin: 1.5rem 0 0.5rem 0;
    color: var(--text-primary);
}

.detail-body p {
    margin-bottom: 1rem;
}

.detail-body code {
    background-color: var(--secondary-bg);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: 'Menlo', monospace;
    font-size: 0.9rem;
}

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

.detail-body pre code {
    background: none;
    padding: 0;
    color: #d4d4d4;
}

.detail-body blockquote {
    border-left: 3px solid var(--accent-color);
    padding-left: 1rem;
    margin: 1rem 0;
    color: var(--text-tertiary);
    font-style: italic;
}

.detail-body ul,
.detail-body ol {
    margin: 1rem 0 1rem 2rem;
}

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

.detail-body a {
    color: var(--accent-color);
    text-decoration: none;
}

.detail-body a:hover {
    text-decoration: underline;
    color: var(--accent-hover);
}

/* ==================== Footer ==================== */
.footer {
    background-color: var(--secondary-bg);
    padding: 2rem 1.5rem;
    text-align: center;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    margin-top: 4rem;
}

/* ==================== Animations ==================== */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==================== Responsive Design ==================== */
@media (max-width: 768px) {
    .nav-right {
        gap: 1rem;
    }

    .nav-links {
        gap: 1rem;
        font-size: 0.85rem;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .hero-content p {
        font-size: 1rem;
    }

    .section {
        padding: 2rem 0;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .modal-content {
        width: 95%;
    }

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

    .form-actions button {
        width: 100%;
    }

    .article-meta {
        font-size: 0.8rem;
    }

    .detail-title {
        font-size: 1.5rem;
    }

    .detail-meta {
        flex-direction: column;
        gap: 0.5rem;
    }
}

@media (max-width: 480px) {
    .main-container,
    .nav-container {
        padding: 0 1rem;
    }

    .hero-content h1 {
        font-size: 1.5rem;
    }

    .hero-content p {
        font-size: 0.9rem;
    }

    .section-header h2 {
        font-size: 1.5rem;
    }

    .article-card {
        padding: 1rem;
    }

    .nav-right {
        gap: 0.5rem;
    }

    .auth-btn {
        padding: 0.4rem 0.8rem;
        font-size: 0.8rem;
    }
}