:root {
    --bg-main: #f3f6f9;
    --bg-sidebar: #ffffff;
    --bg-panel: #ffffff;
    
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-light: #eff6ff;
    
    --border: #e2e8f0;
    --border-focus: #93c5fd;
    
    --success: #10b981;
    --danger: #ef4444;
    
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    
    --shadow-sm: 0 1px 2px 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);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
}

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

/* Sidebar */
.sidebar {
    width: 280px;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    padding: 24px 16px;
    z-index: 10;
    box-shadow: var(--shadow-sm);
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 40px;
    padding: 0 12px;
}

.logo-icon {
    font-size: 24px;
}

.brand h1 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.sidebar nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 12px 16px;
    border: none;
    background: transparent;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    text-align: left;
    transition: all 0.2s ease;
}

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

.nav-btn.active {
    background-color: var(--accent-light);
    color: var(--accent);
    font-weight: 600;
}

.sidebar-footer {
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.primary-btn {
    width: 100%;
    padding: 14px;
    background-color: var(--accent);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: background-color 0.2s;
    box-shadow: 0 2px 4px rgba(59, 130, 246, 0.3);
}

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

.status-msg {
    margin-top: 12px;
    font-size: 0.85rem;
    text-align: center;
    min-height: 20px;
}
.status-msg.success { color: var(--success); }
.status-msg.error { color: var(--danger); }

/* Main Content */
.main-content {
    flex: 1;
    padding: 32px 40px;
    overflow-y: auto;
}

.view-section {
    display: none;
    height: 100%;
    flex-direction: column;
}

.view-section.active {
    display: flex;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

.section-header {
    margin-bottom: 24px;
}

.section-header h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.section-header p {
    color: var(--text-secondary);
}

/* Layout for Lists and Details */
.content-layout {
    display: flex;
    gap: 24px;
    flex: 1;
    min-height: 0; /* for flex child scrolling */
}

/* List Panel */
.list-panel {
    width: 320px;
    background-color: var(--bg-panel);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.panel-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: #fafbfc;
}

.panel-header h3 {
    font-size: 1rem;
    font-weight: 600;
}

.icon-btn {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: none;
    background-color: var(--accent-light);
    color: var(--accent);
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s;
}

.icon-btn:hover {
    background-color: var(--accent);
    color: white;
}

.item-list {
    list-style: none;
    overflow-y: auto;
    flex: 1;
}

.list-item {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    transition: background-color 0.2s;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.list-header {
    padding: 8px 20px;
    background-color: #f8fafc;
    color: var(--text-secondary);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    position: sticky;
    top: 0;
    z-index: 2;
    border-bottom: 1px solid var(--border);
    border-top: 1px solid var(--border);
}
.item-list > .list-header:first-child {
    border-top: none;
}

.list-item:hover {
    background-color: var(--bg-main);
}

.list-item.selected {
    background-color: var(--accent-light);
    border-left: 4px solid var(--accent);
}

.item-name {
    font-weight: 500;
}

.delete-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.2s, color 0.2s;
}

.list-item:hover .delete-btn {
    opacity: 1;
}

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

/* Detail Panel */
.detail-panel {
    flex: 1;
    background-color: var(--bg-panel);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
    padding: 32px;
    overflow-y: auto;
}

.empty-state {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-style: italic;
}

/* Forms */
.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
}

/* Grid for Availabilities */
.week-grid {
    display: grid;
    grid-template-columns: auto repeat(5, 1fr);
    gap: 8px;
    margin-top: 12px;
}

.grid-header {
    text-align: center;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 8px;
}

.grid-row-label {
    display: flex;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.grid-cell {
    background-color: var(--success);
    border-radius: var(--radius-sm);
    height: 40px;
    cursor: pointer;
    transition: transform 0.1s, opacity 0.2s;
    opacity: 0.8;
}

.grid-cell:hover {
    transform: scale(1.05);
    opacity: 1;
}

.grid-cell.unavailable {
    background-color: var(--border);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: normal !important;
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}