/* Base Variables */
:root {
    --font-primary: 'Inter', system-ui, sans-serif;
    --color-bg: #f9fafb;
    --color-surface: #ffffff;
    --color-primary: #2563eb;
    --color-primary-hover: #1e40af;
    --color-text: #111827;
    --color-muted: #6b7280;
    --color-border: #e5e7eb;
    --radius: 0.5rem;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
}

/* Global Reset */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* Layout */
body {
    font-family: var(--font-primary);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
}

/* Header */
header {
    background: var(--color-primary);
    color: #fff;
    padding: 1rem 0;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
header .logo {
    font-size: 1.5rem;
    font-weight: 700;
}
header nav {
    margin-top: 0.5rem;
}
header nav a {
    color: #fff;
    text-decoration: none;
    margin-right: 1rem;
    font-weight: 500;
}
header nav a:hover {
    opacity: 0.85;
}

/* Forum List */
.forum-list {
    display: grid;
    gap: 1.5rem;
    margin-top: 2rem;
}
.forum-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 1.25rem;
    transition: transform 0.2s;
}
.forum-card:hover {
    transform: translateY(-2px);
}
.forum-card h2 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}
.forum-card p {
    color: var(--color-muted);
    margin-bottom: 0.75rem;
}
.forum-card .meta {
    font-size: 0.875rem;
    color: var(--color-muted);
}

/* Thread View */
.thread {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-top: 2rem;
}
.thread-header {
    padding: 1rem;
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.thread-header h1 {
    font-size: 1.5rem;
    color: var(--color-primary);
}
.thread-header .actions button {
    background: var(--color-primary);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    padding: 0.5rem 1rem;
    cursor: pointer;
    font-weight: 500;
}
.thread-header .actions button:hover {
    background: var(--color-primary-hover);
}
.post {
    padding: 1rem;
    border-bottom: 1px solid var(--color-border);
}
.post:last-child {
    border-bottom: none;
}
.post .author {
    font-weight: 600;
    color: var(--color-primary);
}
.post .timestamp {
    font-size: 0.85rem;
    color: var(--color-muted);
    margin-left: 0.5rem;
}
.post .content {
    margin-top: 0.5rem;
}

/* Reply Form */
.reply-form {
    margin-top: 1.5rem;
    padding: 1rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.reply-form textarea {
    width: 100%;
    min-height: 120px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 0.75rem;
    resize: vertical;
    font-family: inherit;
}
.reply-form button {
    margin-top: 0.75rem;
    background: var(--color-primary);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    padding: 0.5rem 1.25rem;
    cursor: pointer;
    font-weight: 500;
}
.reply-form button:hover {
    background: var(--color-primary-hover);
}

/* Responsive */
@media (max-width: 768px) {
    header .logo,
    header nav a {
        display: block;
        text-align: center;
    }
    .forum-list {
        grid-template-columns: 1fr;
    }
    .thread-header {
        flex-direction: column;
        align-items: flex-start;
    }
    .thread-header .actions {
        margin-top: 0.5rem;
    }
}