:root {
    --warm-sunrise: #FF9A56;
    --hope-gold: #FFD93D;
    --calm-sky: #6BC4E8;
    --growth-green: #4CAF93;
    --deep-night: #1a1f2e;
    --soft-cloud: #F8F9FD;
    --warm-gray: #6B7280;
    --card-bg: #FFFFFF;
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
}

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

body {
    font-family: 'Noto Sans SC', sans-serif;
    background: linear-gradient(135deg, #FFF5EB 0%, #E8F4F8 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Header */
header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1.2rem 0;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
    animation: slideDown 0.6s ease-out;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: 'Noto Serif SC', serif;
    font-size: 1.8rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--warm-sunrise), var(--hope-gold));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
}

.logo::before {
    content: '🌅';
    font-size: 2rem;
    filter: drop-shadow(0 2px 4px rgba(255, 154, 86, 0.3));
}

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

.nav-links a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
    cursor: pointer;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--warm-sunrise), var(--hope-gold));
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-avatar-small {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--warm-sunrise), var(--hope-gold));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, var(--warm-sunrise), var(--hope-gold));
    color: white;
    padding: 0.7rem 1.8rem;
    border-radius: 50px;
    border: none;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(255, 154, 86, 0.3);
    font-size: 0.95rem;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(255, 154, 86, 0.4);
}

.btn-secondary {
    background: white;
    color: var(--warm-sunrise);
    padding: 0.7rem 1.8rem;
    border-radius: 50px;
    border: 2px solid var(--warm-sunrise);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-secondary:hover {
    background: var(--warm-sunrise);
    color: white;
}

/* Main Content */
.main-content {
    display: grid;
    grid-template-columns: 1fr 350px;
    gap: 2rem;
    padding: 2rem 0;
}

.content-area {
    min-height: 500px;
}

.sidebar {
    position: sticky;
    top: 100px;
    height: fit-content;
}

/* Categories */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.category-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    transition: all 0.4s ease;
    position: relative;
    overflow: hidden;
    cursor: pointer;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--warm-sunrise), var(--hope-gold));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.category-card:hover::before {
    transform: scaleX(1);
}

.category-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.12);
}

.category-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    display: block;
}

.category-card h3 {
    font-size: 1.4rem;
    margin-bottom: 0.8rem;
    color: var(--text-primary);
}

.category-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.category-stats {
    display: flex;
    gap: 1.5rem;
    margin-top: 1.2rem;
    padding-top: 1.2rem;
    border-top: 1px solid #E5E7EB;
}

.category-stat {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.category-stat strong {
    color: var(--warm-sunrise);
    font-weight: 600;
}

/* Filter Tabs */
.filter-tabs {
    display: flex;
    gap: 1rem;
    background: var(--card-bg);
    padding: 0.5rem;
    border-radius: 50px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    margin-bottom: 2rem;
}

.tab {
    padding: 0.6rem 1.5rem;
    border: none;
    background: transparent;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all 0.3s ease;
}

.tab.active {
    background: linear-gradient(135deg, var(--warm-sunrise), var(--hope-gold));
    color: white;
    box-shadow: 0 4px 15px rgba(255, 154, 86, 0.3);
}

/* Post Card */
.post-card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 1.8rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
    transition: all 0.3s ease;
    animation: fadeIn 0.5s ease-out;
}

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

.post-card:hover {
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.1);
    transform: translateX(5px);
}

.post-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.user-avatar {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--calm-sky), var(--growth-green));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.post-meta {
    flex: 1;
}

.username {
    font-weight: 600;
    color: var(--text-primary);
    display: block;
}

.post-time {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.post-tag {
    background: rgba(255, 154, 86, 0.1);
    color: var(--warm-sunrise);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.post-content h4 {
    font-size: 1.2rem;
    margin-bottom: 0.6rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: color 0.3s ease;
}

.post-content h4:hover {
    color: var(--warm-sunrise);
}

.post-content p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.post-content p.expanded {
    -webkit-line-clamp: unset;
}

.post-footer {
    display: flex;
    gap: 2rem;
    padding-top: 1rem;
    border-top: 1px solid #E5E7EB;
}

.post-action {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
    user-select: none;
}

.post-action:hover {
    color: var(--warm-sunrise);
}

.post-action.liked {
    color: var(--warm-sunrise);
}

/* Comment Section */
.comments-section {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 2px solid #E5E7EB;
    display: none;
}

.comment {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    padding: 1rem;
    background: var(--soft-cloud);
    border-radius: 12px;
}

.comment-avatar {
    width: 35px;
    height: 35px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--calm-sky), var(--growth-green));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    flex-shrink: 0;
}

.comment-content {
    flex: 1;
}

.comment-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.comment-author {
    font-weight: 600;
    color: var(--text-primary);
}

.comment-time {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.comment-text {
    color: var(--text-secondary);
    line-height: 1.6;
}

.comment-input-area {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.comment-input-area input {
    flex: 1;
    padding: 0.8rem 1.2rem;
    border: 2px solid #E5E7EB;
    border-radius: 50px;
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.3s ease;
}

.comment-input-area input:focus {
    border-color: var(--warm-sunrise);
}

.comment-input-area button {
    padding: 0.8rem 1.5rem;
}

/* Sidebar Cards */
.stats-card, .hot-topics, .quick-actions {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
}

.stats-card h3, .hot-topics h3 {
    font-size: 1.1rem;
    margin-bottom: 1.2rem;
    color: var(--text-primary);
}

.stat-item {
    display: flex;
    justify-content: space-between;
    padding: 0.8rem 0;
    border-bottom: 1px solid #E5E7EB;
}

.stat-item:last-child {
    border-bottom: none;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.stat-value {
    font-weight: 700;
    font-size: 1.1rem;
    background: linear-gradient(135deg, var(--warm-sunrise), var(--hope-gold));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.topic-item {
    padding: 0.8rem 1rem;
    background: var(--soft-cloud);
    border-radius: 10px;
    margin-bottom: 0.8rem;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--text-secondary);
}

.topic-item:hover {
    background: rgba(255, 154, 86, 0.1);
    color: var(--warm-sunrise);
    transform: translateX(5px);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
    animation: fadeIn 0.3s ease-out;
}

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

.modal-content {
    background: white;
    padding: 2.5rem;
    border-radius: 20px;
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: slideUp 0.3s ease-out;
    position: relative;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.close {
    color: var(--text-secondary);
    float: right;
    font-size: 2rem;
    font-weight: bold;
    cursor: pointer;
    line-height: 1;
    position: absolute;
    right: 1.5rem;
    top: 1.5rem;
}

.close:hover {
    color: var(--warm-sunrise);
}

.modal-header {
    margin-bottom: 2rem;
}

.auth-tabs {
    display: flex;
    gap: 1rem;
    border-bottom: 2px solid #E5E7EB;
}

.auth-tab {
    padding: 0.8rem 2rem;
    cursor: pointer;
    color: var(--text-secondary);
    font-weight: 500;
    transition: all 0.3s ease;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
}

.auth-tab.active {
    color: var(--warm-sunrise);
    border-bottom-color: var(--warm-sunrise);
}

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

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

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.8rem 1.2rem;
    border: 2px solid #E5E7EB;
    border-radius: 10px;
    font-size: 0.95rem;
    font-family: 'Noto Sans SC', sans-serif;
    outline: none;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    border-color: var(--warm-sunrise);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

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

.loading::after {
    content: '';
    display: inline-block;
    width: 40px;
    height: 40px;
    border: 4px solid #E5E7EB;
    border-top-color: var(--warm-sunrise);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-top: 1rem;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* About Section */
.about-section {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
}

.about-section h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--warm-sunrise), var(--hope-gold));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

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

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

.about-section li {
    padding: 0.8rem 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: 2rem;
}

.about-section li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--growth-green);
    font-weight: bold;
}

/* Responsive */
@media (max-width: 968px) {
    .main-content {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

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

    .nav-links {
        display: none;
    }

    .logo {
        font-size: 1.5rem;
    }

    .modal-content {
        padding: 2rem;
    }
}

/* Success Message */
.success-message {
    position: fixed;
    top: 100px;
    right: 2rem;
    background: var(--growth-green);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2);
    z-index: 3000;
    animation: slideInRight 0.3s ease-out;
}

@keyframes slideInRight {
    from {
        transform: translateX(400px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.error-message {
    background: #EF4444;
}