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

:root {
    --text: #2c3e50;
    --text-light: #666;
    --bg: #fafafa;
    --card-bg: #fff;
    --border: #e0e0e0;
    --accent: #3498db;
    --accent-dark: #2980b9;
}

body {
    font-family: Georgia, 'Times New Roman', serif;
    line-height: 1.7;
    color: var(--text);
    background: var(--bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navigation */
nav {
    background: var(--card-bg);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .logo {
    font-size: 1.25rem;
    font-weight: bold;
    color: var(--text);
    text-decoration: none;
}

nav .nav-links a {
    margin-left: 2rem;
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.95rem;
}

nav .nav-links a:hover {
    color: var(--accent);
}

nav .user-info {
    margin-left: 2rem;
    color: var(--text);
    font-size: 0.95rem;
    font-weight: bold;
}

/* Main Content */
main {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    flex: 1;
    width: 100%;
}

/* Hero */
.hero {
    text-align: center;
    margin-bottom: 3rem;
    padding: 2rem 0;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    font-weight: normal;
}

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

/* Sort Bar */
.sort-bar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
    font-size: 0.85rem;
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.sort-label {
    color: var(--text-light);
}

.sort-option {
    color: var(--text-light);
    text-decoration: none;
    padding: 0.25rem 0.5rem;
    border-radius: 3px;
}

.sort-option:hover {
    color: var(--accent);
}

.sort-option.active {
    color: var(--accent);
    background: #e8f4fc;
}

/* Problem Cards */
.problems-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.problem-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.problem-card > .vote-section {
    flex-shrink: 0;
}

.problem-content {
    flex: 1;
}

.problem-card h2 {
    font-size: 1.3rem;
    font-weight: normal;
    margin-bottom: 0.5rem;
}

.problem-card h2 a {
    color: var(--text);
    text-decoration: none;
}

.problem-card h2 a:hover {
    color: var(--accent);
}

.problem-card .preview {
    color: var(--text-light);
    margin: 0.75rem 0;
    font-size: 0.95rem;
}

.problem-card .meta {
    font-size: 0.85rem;
    color: var(--text-light);
    display: flex;
    justify-content: space-between;
}

.categories {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.category {
    display: inline-block;
    background: #f0f0f0;
    padding: 0.2rem 0.6rem;
    border-radius: 3px;
    font-size: 0.8rem;
    color: var(--text-light);
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.category.active {
    background: var(--accent);
    color: white;
}

/* Vote Section */
.vote-section {
    display: flex;
    align-items: flex-start;
}

.vote-section form {
    margin: 0;
}

.vote-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--card-bg);
    cursor: pointer;
    transition: all 0.15s ease;
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.vote-btn:hover {
    border-color: var(--accent);
    background: #f8f9fa;
}

.vote-btn.voted {
    border-color: var(--accent);
    background: #e8f4fc;
}

.vote-btn.voted .vote-arrow {
    color: var(--accent);
}

.vote-btn.disabled {
    cursor: default;
    opacity: 0.7;
}

.vote-arrow {
    font-size: 1rem;
    color: var(--text-light);
    line-height: 1;
}

.vote-count {
    font-size: 0.9rem;
    font-weight: bold;
    color: var(--text);
}

.vote-section.large .vote-btn {
    padding: 0.75rem 1rem;
}

.vote-section.large .vote-arrow {
    font-size: 1.25rem;
}

.vote-section.large .vote-count {
    font-size: 1.1rem;
}

.vote-btn-small {
    padding: 0.35rem 0.5rem;
}

.vote-btn-small .vote-arrow {
    font-size: 0.8rem;
}

.vote-btn-small .vote-count {
    font-size: 0.8rem;
}

/* Ratings Display */
.problem-stats {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.75rem;
}

.ratings-display {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.ratings-display.large {
    gap: 0.5rem;
}

.rating-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.rating-label {
    font-size: 0.7rem;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.ratings-display.large .rating-label {
    font-size: 0.75rem;
}

.rating-value {
    font-size: 1rem;
    font-weight: bold;
    color: var(--text);
}

.ratings-display.large .rating-value {
    font-size: 1.25rem;
}

.rating-count {
    font-size: 0.7rem;
    color: var(--text-light);
}

/* Rating Section (on problem page) */
.rating-section {
    background: var(--card-bg);
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    margin-bottom: 2rem;
}

.rating-section h2 {
    font-size: 1.3rem;
    font-weight: normal;
    margin-bottom: 1rem;
}

.rating-form {
    margin-bottom: 0.5rem;
}

.rating-inputs {
    display: flex;
    gap: 2rem;
    margin-bottom: 1rem;
}

.rating-input-group {
    flex: 1;
}

.rating-input-group label {
    font-weight: bold;
    margin-bottom: 0.25rem;
}

.rating-hint {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 0.5rem;
}

.rating-input-group select {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
}

.rating-input-group select:focus {
    outline: none;
    border-color: var(--accent);
}

.your-rating {
    font-size: 0.9rem;
    color: var(--text-light);
    font-style: italic;
}

/* Problem Detail */
.problem-detail {
    background: var(--card-bg);
    padding: 2rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    margin-bottom: 2rem;
}

.problem-detail h1 {
    font-size: 1.8rem;
    font-weight: normal;
    margin-bottom: 0.75rem;
}

.problem-detail .meta {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
}

.problem-detail .meta span {
    margin-right: 1.5rem;
}

.problem-detail .description {
    white-space: pre-wrap;
}

.problem-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.problem-header > .vote-section {
    flex-shrink: 0;
}

.problem-header .problem-stats {
    margin-left: auto;
}

.problem-header-content {
    flex: 1;
}

/* Discussion */
.discussion {
    margin-bottom: 2rem;
}

.discussion h2 {
    font-size: 1.3rem;
    font-weight: normal;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border);
}

.comments {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.comment {
    background: var(--card-bg);
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: 4px;
}

.comment-header {
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.comment-header strong {
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.comment-date {
    color: var(--text-light);
    margin-left: 1rem;
}

.comment p {
    white-space: pre-wrap;
}

.no-comments {
    color: var(--text-light);
    font-style: italic;
    margin-bottom: 2rem;
}

/* Forms */
.submit-form,
.comment-form {
    background: var(--card-bg);
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
}

.submit-page h1,
.about-page h1 {
    font-size: 2rem;
    font-weight: normal;
    margin-bottom: 1rem;
}

.submit-page > p {
    color: var(--text-light);
    margin-bottom: 2rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

input[type="text"],
textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-family: inherit;
    font-size: 1rem;
    margin-bottom: 1.25rem;
}

input[type="text"]:focus,
textarea:focus {
    outline: none;
    border-color: var(--accent);
}

textarea {
    resize: vertical;
    min-height: 100px;
}

button {
    background: var(--accent);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

button:hover {
    background: var(--accent-dark);
}

.comment-form h3 {
    font-size: 1.1rem;
    font-weight: normal;
    margin-bottom: 1rem;
}

/* About Page */
.about-page h2 {
    font-size: 1.4rem;
    font-weight: normal;
    margin-top: 2rem;
    margin-bottom: 0.75rem;
}

.about-page ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.about-page li {
    margin-bottom: 0.5rem;
}

/* Flash Messages */
.flash {
    background: #e8f4f8;
    border: 1px solid #bee5eb;
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1.5rem;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-light);
}

.empty-state a {
    color: var(--accent);
}

/* Back Link */
.back-link {
    display: inline-block;
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.95rem;
}

.back-link:hover {
    color: var(--accent);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-light);
    font-size: 0.9rem;
    border-top: 1px solid var(--border);
}

/* Content with Sidebar */
.content-with-sidebar {
    display: flex;
    gap: 2rem;
}

.content-with-sidebar .problems-list {
    flex: 1;
}

.sidebar {
    width: 200px;
    flex-shrink: 0;
}

.sidebar h3 {
    font-size: 1rem;
    font-weight: normal;
    margin-bottom: 1rem;
    color: var(--text-light);
}

.category-list {
    list-style: none;
}

.category-list li {
    margin-bottom: 0.5rem;
}

.category-list a {
    color: var(--text);
    text-decoration: none;
    font-size: 0.95rem;
}

.category-list a:hover {
    color: var(--accent);
}

.category-list li.active a {
    color: var(--accent);
    font-weight: bold;
}

/* Auth Pages */
.auth-page {
    max-width: 400px;
    margin: 2rem auto;
}

.auth-page h1 {
    font-size: 2rem;
    font-weight: normal;
    margin-bottom: 2rem;
    text-align: center;
}

.auth-form {
    background: var(--card-bg);
    padding: 2rem;
    border: 1px solid var(--border);
    border-radius: 4px;
}

.auth-form small,
.submit-form small {
    display: block;
    color: var(--text-light);
    font-size: 0.85rem;
    margin-top: -1rem;
    margin-bottom: 1rem;
}

input[type="password"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-family: inherit;
    font-size: 1rem;
    margin-bottom: 1.25rem;
}

input[type="password"]:focus {
    outline: none;
    border-color: var(--accent);
}

.auth-link {
    text-align: center;
    margin-top: 1.5rem;
    color: var(--text-light);
}

.auth-link a {
    color: var(--accent);
}

/* Login Prompt */
.login-prompt {
    background: var(--card-bg);
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    text-align: center;
    color: var(--text-light);
}

.login-prompt a {
    color: var(--accent);
}

/* Category as link */
a.category {
    text-decoration: none;
}

a.category:hover {
    background: #e0e0e0;
}

/* Responsive */
@media (max-width: 600px) {
    nav {
        flex-direction: column;
        gap: 1rem;
    }

    nav .nav-links a {
        margin-left: 1rem;
    }

    nav .nav-links a:first-child {
        margin-left: 0;
    }

    main {
        padding: 1rem;
    }

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

    .content-with-sidebar {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        order: -1;
    }

    .category-list {
        display: flex;
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .category-list li {
        margin: 0;
    }

    .category-list a {
        display: inline-block;
        background: #f0f0f0;
        padding: 0.25rem 0.75rem;
        border-radius: 3px;
    }
}

/* Admin Styles */
.admin-link {
    color: #e74c3c !important;
}

.admin-page {
    max-width: 800px;
    margin: 0 auto;
}

.admin-page h1 {
    font-size: 2rem;
    font-weight: normal;
    margin-bottom: 2rem;
}

.admin-section {
    background: var(--card-bg);
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    margin-bottom: 2rem;
}

.admin-section h2 {
    font-size: 1.3rem;
    font-weight: normal;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border);
}

.admin-table {
    width: 100%;
    border-collapse: collapse;
}

.admin-table th,
.admin-table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.admin-table th {
    font-weight: bold;
    color: var(--text-light);
    font-size: 0.9rem;
}

.admin-table .actions {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.admin-form {
    background: var(--card-bg);
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
}

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

.btn-cancel {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: #f0f0f0;
    color: var(--text);
    text-decoration: none;
    border-radius: 4px;
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.btn-cancel:hover {
    background: #e0e0e0;
}

.btn-small {
    display: inline-block;
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
    background: var(--accent);
    color: white;
    text-decoration: none;
    border: none;
    border-radius: 3px;
    cursor: pointer;
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

.btn-small:hover {
    background: var(--accent-dark);
}

.btn-danger {
    background: #e74c3c;
}

.btn-danger:hover {
    background: #c0392b;
}

.btn-success {
    background: #27ae60;
}

.btn-success:hover {
    background: #1e8449;
}

.inline {
    display: inline;
}

.admin-actions {
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
    display: flex;
    gap: 0.5rem;
}

.admin-actions .btn-small {
    min-width: 110px;
    text-align: center;
}

.admin-comment-actions {
    margin-left: auto;
    display: inline-flex;
    gap: 0.5rem;
    align-items: center;
}

.comment-header {
    display: flex;
    align-items: center;
}