:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --background-color: #f8f9fa;
    --text-color: #333;
    --border-color: #ddd;
    --alert-error: #e74c3c;
    --alert-warning: #f39c12;
    --alert-info: #3498db;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1.5rem;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

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

header p {
    color: #666;
    font-size: 1.1rem;
}

.editor-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--secondary-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

textarea {
    width: 100%;
    height: 400px;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

button {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    padding: 0.75rem;
    margin-top: 1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

button:hover:not(:disabled) {
    background-color: #2980b9;
}

button:disabled {
    background-color: #a5ccea;
    cursor: not-allowed;
    opacity: 0.8;
}

.spinner {
    display: none;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
    margin-right: 10px;
}

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

button.loading .spinner {
    display: inline-block;
}

.preview {
    background-color: white;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    height: 400px;
    overflow-y: auto;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.preview .placeholder {
    color: #999;
    font-style: italic;
    text-align: center;
    margin-top: 2rem;
}

.flashes {
    margin-bottom: 1.5rem;
}

.alert {
    padding: 0.75rem 1rem;
    border-radius: 6px;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.alert.error { background-color: #fadbd8; color: var(--alert-error); border: 1px solid #f5b7b1; }
.alert.warning { background-color: #fef5e7; color: var(--alert-warning); border: 1px solid #f9e79f; }
.alert.info { background-color: #ebf5fb; color: var(--alert-info); border: 1px solid #d6eaf8; }

/* Markdown Preview Styles */
.preview h1 { font-size: 1.5rem; margin-top: 0; }
.preview h2 { font-size: 1.3rem; }
.preview blockquote { border-left: 4px solid #eee; padding-left: 1rem; color: #666; margin-left: 0; }
.preview pre { background-color: #f4f4f4; padding: 1rem; border-radius: 4px; overflow-x: auto; }
.preview code { font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace; background-color: #f4f4f4; padding: 0.2rem 0.4rem; border-radius: 3px; }

@media (max-width: 768px) {
    .editor-grid {
        grid-template-columns: 1fr;
    }
}