* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s, color 0.3s;
}

:root {
    --bg-primary: #f5f7fa;
    --bg-secondary: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --accent-color: #4A90E2;
    --border-color: #eee;
}

[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #cccccc;
    --accent-color: #64B5F6;
    --border-color: #404040;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    min-height: 100vh;
    background: var(--bg-primary);
    padding: 1rem;
    color: var(--text-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

.notepad {
    background: var(--bg-secondary);
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.notepad-header {
    background: var(--accent-color);
    color: white;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.notepad-header h1 {
    font-size: 1.5rem;
    font-weight: 500;
}

.controls {
    display: flex;
    gap: 1rem;
    padding: 0.5rem 1rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.control-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

button {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 4px;
    background: var(--accent-color);
    color: white;
    cursor: pointer;
}

button:hover {
    opacity: 0.9;
}

.tabs {
    display: flex;
    gap: 0.25rem;
    padding: 0.5rem 1rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    overflow-x: auto;
}

.tab {
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    background: var(--bg-primary);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.tab span.tab-name {
    cursor: text;
    padding: 2px 4px;
    border-radius: 2px;
}

.tab span.tab-name:hover {
    background: rgba(255, 255, 255, 0.1);
}

.tab input.tab-name-input {
    background: none;
    border: none;
    color: inherit;
    font: inherit;
    padding: 2px 4px;
    width: auto;
    min-width: 50px;
}

.tab input.tab-name-input:focus {
    outline: none;
    background: rgba(255, 255, 255, 0.1);
}

.tab-close {
    border-radius: 50%;
    width: 16px;
    height: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
}

.editor-container {
    position: relative;
    display: flex;
}

.line-numbers {
    padding: 1rem 0.5rem;
    background: var(--bg-primary);
    border-right: 1px solid var(--border-color);
    color: var(--text-secondary);
    text-align: right;
    user-select: none;
}

#notepad-content {
    width: 100%;
    height: 400px;
    padding: 1rem;
    border: none;
    resize: none;
    font-size: 1rem;
    line-height: 1.5;
    color: var(--text-primary);
    background: var(--bg-secondary);
}

#notepad-content:focus {
    outline: none;
}

.status-bar {
    padding: 0.5rem 1rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.stats {
    display: flex;
    gap: 1rem;
}

select {
    padding: 0.25rem;
    border-radius: 4px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}