/* ===================================
   Markdown Live Editor - Main Styles
   Version: 0.1.0
   =================================== */

/* CSS Variables */
:root {
    /* Colors - Light Theme (Default) */
    --color-primary: #3498db;
    --color-primary-dark: #2980b9;
    --color-success: #27ae60;
    --color-danger: #e74c3c;
    --color-warning: #f39c12;
    --color-info: #3498db;
    
    --color-background: #ffffff;
    --color-surface: #f8f9fa;
    --color-surface-hover: #e9ecef;
    --color-border: #dee2e6;
    --color-text: #212529;
    --color-text-secondary: #6c757d;
    --color-text-muted: #adb5bd;
    
    /* Editor Specific */
    --color-editor-bg: #ffffff;
    --color-editor-text: #212529;
    --color-preview-bg: #ffffff;
    --color-preview-text: #212529;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    /* Negative spacing for special layouts */
    --spacing-lg-negative: -24px;
    
    /* Typography */
    --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
    
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    
    --line-height-base: 1.6;
    --line-height-heading: 1.2;
    
    /* Layout */
    --toolbar-height: 60px;
    --footer-height: 40px;
    --border-radius: 4px;
    --border-width: 1px;
    
    /* Shadows */
    --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);
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow: hidden;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

/* Toolbar */
.toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--toolbar-height);
    padding: 0 var(--spacing-md);
    background-color: var(--color-surface);
    border-bottom: var(--border-width) solid var(--color-border);
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.toolbar__section {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.toolbar__section--left {
    flex: 0 0 auto;
}

.toolbar__section--center {
    flex: 1 1 auto;
    display: flex;
    justify-content: center;
    gap: var(--spacing-xs);
    overflow-x: auto;
}

.toolbar__section--right {
    flex: 0 0 auto;
    display: flex;
    gap: var(--spacing-sm);
}

.toolbar__title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
    white-space: nowrap;
}

.toolbar__group {
    display: flex;
    gap: var(--spacing-xs);
    align-items: center;
}

.toolbar__separator {
    width: 1px;
    height: 24px;
    background-color: var(--color-border);
    margin: 0 var(--spacing-xs);
}

.toolbar__button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    min-width: 36px;
    height: 36px;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text);
    background-color: var(--color-background);
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
}

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

.toolbar__button:active {
    transform: translateY(1px);
}

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

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

.toolbar__button--primary:hover {
    background-color: var(--color-primary-dark);
}

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

.toolbar__button--danger:hover {
    background-color: #c0392b;
}

.toolbar__select {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-sm);
    color: var(--color-text);
    background-color: var(--color-background);
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

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

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

/* Main Content */
.main-content {
    display: flex;
    flex-direction: column;
    gap: 0;
    height: calc(100vh - var(--toolbar-height) - var(--footer-height));
    overflow: hidden;
}

/* Panel Styles */
.editor-panel,
.preview-panel {
    display: flex;
    flex-direction: column;
    overflow: hidden;
    flex: 1;
    transition: flex var(--transition-base), min-height var(--transition-base), max-height var(--transition-base);
    border-bottom: var(--border-width) solid var(--color-border);
}

.preview-panel {
    border-bottom: none;
}

.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--color-surface);
    border-bottom: var(--border-width) solid var(--color-border);
}

.panel-header__controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.panel-title {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text-secondary);
}

.panel-button {
    padding: var(--spacing-xs);
    background: none;
    border: none;
    cursor: pointer;
    font-size: var(--font-size-lg);
    opacity: 0.6;
    transition: all var(--transition-fast);
}

.panel-button:hover {
    opacity: 1;
    transform: scale(1.1);
}

.panel-button:active {
    transform: scale(0.95);
}

.save-indicator {
    font-size: var(--font-size-sm);
    color: var(--color-success);
    font-weight: 500;
    opacity: 0;
    transition: opacity var(--transition-base);
}

.save-indicator.visible {
    opacity: 1;
}

/* Collapsed Panel States - Curtain Effect */
.editor-panel.collapsed {
    flex: 0;
    min-height: 44px;
    max-height: 44px;
    overflow: hidden;
}

.preview-panel.collapsed {
    flex: 0;
    min-height: 44px;
    max-height: 44px;
    overflow: hidden;
}

.editor-panel.collapsed .editor-textarea,
.preview-panel.collapsed .preview-content {
    display: none;
    opacity: 0;
}

/* Expanded Panel States */
.editor-panel.expanded,
.preview-panel.expanded {
    flex: 1;
}

/* Collapsed panel header stays visible and clickable */
.editor-panel.collapsed .panel-header,
.preview-panel.collapsed .panel-header {
    cursor: pointer;
    user-select: none;
}

.editor-panel.collapsed .panel-header:hover,
.preview-panel.collapsed .panel-header:hover {
    background-color: var(--color-surface-hover);
}

.editor-panel.collapsed .save-indicator {
    display: none;
}

/* Editor Textarea */
.editor-textarea {
    flex: 1;
    width: 100%;
    padding: var(--spacing-md);
    font-family: var(--font-family-mono);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--color-editor-text);
    background-color: var(--color-editor-bg);
    border: none;
    resize: none;
    outline: none;
    overflow-y: auto;
    white-space: pre-wrap;
    word-wrap: break-word;
    tab-size: 4;
}

.editor-textarea::placeholder {
    color: var(--color-text-muted);
}

/* Preview Content */
.preview-content {
    flex: 1;
    padding: var(--spacing-md);
    overflow-y: auto;
    background-color: var(--color-preview-bg);
    color: var(--color-preview-text);
}

/* Markdown Preview Styles */
.preview-content h1,
.preview-content h2,
.preview-content h3,
.preview-content h4,
.preview-content h5,
.preview-content h6 {
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
    line-height: var(--line-height-heading);
    color: var(--color-text);
}

.preview-content h1 { font-size: 2em; }
.preview-content h2 { font-size: 1.5em; }
.preview-content h3 { font-size: 1.25em; }
.preview-content h4 { font-size: 1.1em; }
.preview-content h5 { font-size: 1em; }
.preview-content h6 { font-size: 0.9em; }

.preview-content h1:first-child,
.preview-content h2:first-child,
.preview-content h3:first-child {
    margin-top: 0;
}

.preview-content p {
    margin-bottom: var(--spacing-md);
}

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

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

.preview-content ul,
.preview-content ol {
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
}

.preview-content li {
    margin-bottom: var(--spacing-xs);
}

.preview-content code {
    padding: 2px 6px;
    font-family: var(--font-family-mono);
    font-size: 0.9em;
    background-color: var(--color-surface);
    border: var(--border-width) solid var(--color-border);
    border-radius: 3px;
}

.preview-content pre {
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md);
    background-color: var(--color-surface);
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius);
    overflow-x: auto;
}

.preview-content pre code {
    padding: 0;
    background: none;
    border: none;
    display: block;
    white-space: pre;
    word-wrap: normal;
    overflow-x: auto;
}

.preview-content blockquote {
    margin: var(--spacing-md) 0;
    padding: var(--spacing-sm) var(--spacing-md);
    border-left: 4px solid var(--color-primary);
    background-color: var(--color-surface);
    color: var(--color-text-secondary);
}

.preview-content blockquote p:last-child {
    margin-bottom: 0;
}

.preview-content hr {
    margin: var(--spacing-lg) 0;
    border: none;
    border-top: var(--border-width) solid var(--color-border);
}

.preview-content img {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    margin: var(--spacing-md) 0;
}

.preview-content table {
    width: 100%;
    margin-bottom: var(--spacing-md);
    border-collapse: collapse;
}

.preview-content th,
.preview-content td {
    padding: var(--spacing-sm);
    border: var(--border-width) solid var(--color-border);
    text-align: left;
}

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

/* Task List Items */
.preview-content .task-list-item {
    list-style-type: none;
    margin-left: var(--spacing-lg-negative);
    padding-left: var(--spacing-sm);
}

.preview-content .task-list-item input[type="checkbox"] {
    margin-right: var(--spacing-sm);
    vertical-align: middle;
}

/* Strikethrough */
.preview-content del,
.preview-content s {
    text-decoration: line-through;
    opacity: 0.7;
}

/* Mark/Highlight */
.preview-content mark {
    background-color: #fff3cd;
    padding: 0.1em 0.2em;
    border-radius: 2px;
}

/* Subscript and Superscript */
.preview-content sub,
.preview-content sup {
    font-size: 0.75em;
    line-height: 0;
    position: relative;
    vertical-align: baseline;
}

.preview-content sup {
    top: -0.5em;
}

.preview-content sub {
    bottom: -0.25em;
}

/* Keyboard Input */
.preview-content kbd {
    font-family: var(--font-family-mono);
    font-size: 0.85em;
    padding: 0.15em 0.4em;
    background-color: var(--color-surface);
    border: var(--border-width) solid var(--color-border);
    border-radius: 3px;
    box-shadow: inset 0 -1px 0 var(--color-border);
}

/* Definition Lists */
.preview-content dl {
    margin-bottom: var(--spacing-md);
}

.preview-content dt {
    font-weight: 600;
    margin-top: var(--spacing-sm);
}

.preview-content dd {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

/* Details/Summary */
.preview-content details {
    margin-bottom: var(--spacing-md);
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-sm);
}

.preview-content summary {
    cursor: pointer;
    font-weight: 500;
    padding: var(--spacing-xs);
}

.preview-content details[open] summary {
    margin-bottom: var(--spacing-sm);
    border-bottom: var(--border-width) solid var(--color-border);
    padding-bottom: var(--spacing-sm);
}

/* Abbreviations */
.preview-content abbr[title] {
    text-decoration: underline dotted;
    cursor: help;
}

/* Inserted text */
.preview-content ins {
    background-color: #d4edda;
    text-decoration: none;
    padding: 0.1em 0.2em;
    border-radius: 2px;
}

/* Figure and Figcaption */
.preview-content figure {
    margin: var(--spacing-md) 0;
    text-align: center;
}

.preview-content figcaption {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-top: var(--spacing-sm);
}

/* Nested blockquotes */
.preview-content blockquote blockquote {
    margin-left: var(--spacing-md);
    border-left-color: var(--color-text-muted);
}

/* Nested lists */
.preview-content ul ul,
.preview-content ol ol,
.preview-content ul ol,
.preview-content ol ul {
    margin-bottom: 0;
}

/* Footer */
.app-footer {
    display: flex;
    align-items: center;
    justify-content: center;
    height: var(--footer-height);
    padding: 0 var(--spacing-md);
    background-color: var(--color-surface);
    border-top: var(--border-width) solid var(--color-border);
}

.footer-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.footer-text {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

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

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

/* Drop Zone Overlay */
.drop-zone-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(52, 152, 219, 0.9);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    pointer-events: none;
}

.drop-zone-overlay.active {
    display: flex;
    pointer-events: all;
}

.drop-zone-content {
    text-align: center;
}

.drop-zone-text {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: white;
}

/* Scrollbar Styles */
.editor-textarea::-webkit-scrollbar,
.preview-content::-webkit-scrollbar {
    width: 12px;
}

.editor-textarea::-webkit-scrollbar-track,
.preview-content::-webkit-scrollbar-track {
    background: var(--color-surface);
}

.editor-textarea::-webkit-scrollbar-thumb,
.preview-content::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 6px;
}

.editor-textarea::-webkit-scrollbar-thumb:hover,
.preview-content::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-muted);
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-muted {
    color: var(--color-text-muted);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideDown {
    from {
        transform: translateY(-10px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.fade-in {
    animation: fadeIn var(--transition-base);
}

.slide-down {
    animation: slideDown var(--transition-base);
}