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

:root {
    --bg-color: #f8f8f8;
    --text-color: #333;
    --text-secondary: #666;
    --border-color: #e0e0e0;
    --accent-color: #000;
    --success-color: #388e3c;
    --error-color: #d32f2f;
    --sidebar-width: 280px;
    --header-height: 60px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* App Layout */
.app {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: #fff;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.sidebar-header a {
    color: var(--text-color);
    text-decoration: none;
}

.folder-nav {
    flex: 1;
    padding: 15px;
}

.folder-nav ul {
    list-style: none;
}

.folder-nav li {
    position: relative;
}

.folder-nav a {
    display: block;
    padding: 8px 12px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 4px;
    transition: background 0.1s;
}

.folder-nav a:hover {
    background: var(--bg-color);
    color: var(--text-color);
}

.folder-nav a.active {
    background: #000;
    color: #fff;
}

.folder-nav ul ul {
    padding-left: 15px;
    margin-top: 5px;
}

.delete-folder {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 1.2rem;
    opacity: 0;
    transition: opacity 0.1s;
}

.folder-nav li:hover .delete-folder {
    opacity: 1;
}

.delete-folder:hover {
    color: var(--error-color);
}

.sidebar-footer {
    padding: 15px;
    border-top: 1px solid var(--border-color);
}

.folder-form {
    display: flex;
    gap: 8px;
    margin-bottom: 15px;
}

.folder-form input[type="text"] {
    flex: 1;
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 0.9rem;
}

.folder-form button {
    padding: 8px 12px;
    background: var(--accent-color);
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
}

.logout-btn {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
}

.logout-btn:hover {
    color: var(--error-color);
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 30px;
    max-width: 800px;
}

/* Login Page */
.login-container {
    max-width: 400px;
    margin: 100px auto;
    padding: 40px;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.login-container h1 {
    font-size: 2rem;
    margin-bottom: 30px;
    text-align: center;
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Forms */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: 20px;
}

.form-group label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input[type="text"],
.form-group input[type="password"],
.form-group select,
.form-group textarea {
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
}

.form-group textarea {
    resize: vertical;
    min-height: 300px;
    font-family: inherit;
}

.form-group select {
    cursor: pointer;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 20px;
    background: var(--accent-color);
    color: #fff;
    text-decoration: none;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: background 0.1s;
}

.btn:hover {
    background: #333;
}

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

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

.btn-danger {
    background: var(--error-color);
    color: #fff;
}

.btn-danger:hover {
    background: #b71c1c;
}

/* Notes List */
.notes-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.notes-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.notes-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.note-card {
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 20px;
    transition: box-shadow 0.1s;
}

.note-card:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.note-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 10px;
}

.note-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.note-header a {
    color: var(--text-color);
    text-decoration: none;
}

.note-header a:hover {
    text-decoration: underline;
}

.note-date {
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
}

.note-preview {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 10px;
}

.note-actions {
    text-align: right;
}

.delete-btn {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
}

.delete-btn:hover {
    color: var(--error-color);
}

/* Note Form */
.note-form {
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 30px;
}

.form-actions {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
    margin-top: 20px;
}

/* Messages */
.error-message,
.success-message {
    padding: 12px 15px;
    border-radius: 4px;
    margin-bottom: 20px;
}

.error-message {
    background: #ffebee;
    color: var(--error-color);
    border: 1px solid #ffcdd2;
}

.success-message {
    background: #e8f5e9;
    color: var(--success-color);
    border: 1px solid #c8e6c9;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: -var(--sidebar-width);
        z-index: 100;
        transition: left 0.3s;
    }
    
    .sidebar.open {
        left: 0;
    }
    
    .main-content {
        margin-left: 0;
        padding: 20px;
    }
    
    .notes-header {
        flex-direction: column;
        gap: 15px;
        align-items: flex-start;
    }
    
    .form-actions {
        flex-wrap: wrap;
    }
}