:root {
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-mono: 'Fira Code', 'SF Mono', 'Roboto Mono', monospace;

    --primary-color: #3662E1;
    --primary-hover: #2A52CC;
    --primary-light: #EBF0FF;

    --danger-color: #E53E3E;
    --danger-hover: #C53030;

    --text-primary: #1A202C;
    --text-secondary: #4A5568;
    --text-placeholder: #A0AEC0;

    --bg-primary: #FFFFFF;
    --bg-secondary: #F7FAFC;
    --bg-tertiary: #EDF2F7;

    --border-primary: #E2E8F0;
    --border-secondary: #CBD5E0;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);

    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;

    --transition: all 0.2s ease-in-out;
}

.dark-theme {
    --primary-color: #4299E1;
    --primary-hover: #3182CE;
    --primary-light: rgba(66, 153, 225, 0.1);

    --danger-color: #FC8181;
    --danger-hover: #F56565;

    --text-primary: #E2E8F0;
    --text-secondary: #A0AEC0;
    --text-placeholder: #718096;

    --bg-primary: #1A202C;
    --bg-secondary: #2D3748;
    --bg-tertiary: #4A5568;

    --border-primary: #4A5568;
    --border-secondary: #718096;
}

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

body {
    font-family: var(--font-primary);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: var(--transition);
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1.5rem;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-primary);
    box-shadow: var(--shadow-sm);
    z-index: 10;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo h1 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.header-actions .icon-btn {
    color: var(--text-secondary);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 1rem;
    overflow: hidden;
}

.toolbar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--bg-primary);
    padding: 0.5rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-primary);
}

.toolbar-group {
    display: flex;
    gap: 0.25rem;
}

.toolbar-group:not(:last-child) {
    margin-right: 0.5rem;
    padding-right: 0.5rem;
    border-right: 1px solid var(--border-primary);
}

.toolbar-btn {
    background: none;
    border: none;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
}

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

.toolbar-btn.active {
    background-color: var(--primary-light);
    color: var(--primary-color);
}

.editor-container {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    overflow: hidden;
}

.panel {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-md);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: var(--transition);
}

.panel:focus-within {
    box-shadow: 0 0 0 2px var(--primary-color);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-primary);
    background-color: var(--bg-secondary);
}

.panel-header h2 {
    font-size: 0.875rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

#markdown-input, .preview {
    flex: 1;
    padding: 1rem;
    overflow-y: auto;
}

#markdown-input {
    width: 100%;
    border: none;
    resize: none;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    line-height: 1.7;
    background: transparent;
    color: var(--text-primary);
    outline: none;
}

#markdown-input::placeholder {
    color: var(--text-placeholder);
}

.char-count {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-variant-numeric: tabular-nums;
}

.preview {
    line-height: 1.7;
    word-wrap: break-word;
}

.preview h1, .preview h2, .preview h3, .preview h4, .preview h5, .preview h6 {
    margin-top: 1.5em;
    margin-bottom: 0.8em;
    font-weight: 600;
    line-height: 1.3;
}

.preview h1 { font-size: 2rem; border-bottom: 1px solid var(--border-primary); padding-bottom: 0.3em; }
.preview h2 { font-size: 1.5rem; border-bottom: 1px solid var(--border-primary); padding-bottom: 0.3em; }
.preview h3 { font-size: 1.25rem; }
.preview h4 { font-size: 1rem; }

.preview p { margin-bottom: 1em; }

.preview a {
    color: var(--primary-color);
    text-decoration: none;
    border-bottom: 1px solid transparent;
}

.preview a:hover {
    border-bottom-color: var(--primary-hover);
}

.preview ul, .preview ol {
    padding-left: 2em;
    margin-bottom: 1em;
}

.preview blockquote {
    margin: 1.5em 0;
    padding: 0.5em 1.25em;
    border-left: 4px solid var(--primary-color);
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
}

.preview table {
    width: 100%;
    margin: 1.5em 0;
    border-collapse: collapse;
}

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

.preview th {
    background-color: var(--bg-secondary);
    font-weight: 600;
}

.preview pre {
    background-color: var(--bg-secondary);
    padding: 1rem;
    border-radius: var(--radius-sm);
    overflow-x: auto;
    margin: 1.5em 0;
}

.preview code {
    font-family: var(--font-mono);
    background-color: var(--primary-light);
    color: var(--primary-color);
    padding: 0.2em 0.4em;
    border-radius: var(--radius-sm);
    font-size: 0.9em;
}

.preview pre code {
    background: none;
    color: inherit;
    padding: 0;
    font-size: inherit;
}

.app-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1.5rem;
    background-color: var(--bg-primary);
    border-top: 1px solid var(--border-primary);
}

.status-bar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

#status-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: #48BB78; /* Green for ready */
    transition: var(--transition);
}

#status-indicator.loading {
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

.action-buttons {
    display: flex;
    gap: 0.75rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-family: var(--font-primary);
    font-weight: 500;
    font-size: 0.875rem;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    transition: var(--transition);
}

.btn:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
}

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

.btn-secondary:hover {
    background-color: var(--border-primary);
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
    border-color: var(--danger-color);
}

.btn-danger:hover {
    background-color: var(--danger-hover);
    border-color: var(--danger-hover);
}

.icon-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.25rem;
    height: 2.25rem;
    border-radius: var(--radius-sm);
    border: none;
    background: none;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}

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

.icon-sun, .icon-moon {
    display: none;
}

body:not(.dark-theme) .icon-moon {
    display: block;
}

.dark-theme .icon-sun {
    display: block;
}

.modal {
    display: none;
    position: fixed;
    z-index: 100;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.6);
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--bg-primary);
    margin: auto;
    padding: 1.5rem;
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-lg);
    width: 90%;
    max-width: 1200px;
    height: 90%;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

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

.modal-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
}

#fullscreen-preview-content {
    flex: 1;
    overflow-y: auto;
    padding-top: 1rem;
}

#notification-container {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    z-index: 200;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.notification {
    background-color: var(--bg-primary);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
    padding: 1rem 1.5rem;
    max-width: 350px;
    border-left: 4px solid;
    display: flex;
    align-items: center;
    gap: 1rem;
    animation: slideIn 0.3s ease-out, fadeOut 0.3s ease-in 3.7s forwards;
}

@keyframes slideIn {
    from { transform: translateX(120%); }
    to { transform: translateX(0); }
}

@keyframes fadeOut {
    from { opacity: 1; }
    to { opacity: 0; }
}

.notification.success { border-color: #48BB78; }
.notification.error { border-color: var(--danger-color); }
.notification.warning { border-color: #ED8936; }

.notification-content p {
    margin: 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.notification-content strong {
    color: var(--text-primary);
}

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

    .app-footer {
        flex-direction: column;
        gap: 1rem;
    }

    .action-buttons {
        width: 100%;
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    }
}

::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background-color: var(--border-secondary);
    border-radius: 6px;
    border: 3px solid var(--bg-secondary);
}

::-webkit-scrollbar-thumb:hover {
    background-color: var(--text-placeholder);
}

/* Tooltip样式 */
.tooltip {
    position: fixed;
    background-color: var(--text-primary);
    color: var(--bg-primary);
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    font-weight: 500;
    pointer-events: none;
    z-index: 1000;
    white-space: nowrap;
    box-shadow: var(--shadow-md);
    opacity: 0;
    animation: tooltipFadeIn 0.2s ease-out forwards;
}

@keyframes tooltipFadeIn {
    from {
        opacity: 0;
        transform: translateY(-4px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 版权信息样式 */
.copyright {
    text-align: center;
    padding: 0.5rem 0;
    font-size: 0.75rem;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-primary);
    background-color: var(--bg-primary);
}

.copyright a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

.copyright a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}