/* ===== ROOT VARIABLES ===== */
:root {
    /* Colors - Microsoft Teams inspired */
    --primary-bg: #1f1f23;
    --secondary-bg: #2a2a2e;
    --sidebar-bg: #252529;
    --card-bg: #292c33;
    --hover-bg: #3a3d44;
    --border-color: #3a3d44;
    
    /* Accent Colors */
    --accent-primary: #6264a7;
    --accent-secondary: #464775;
    --success-color: #92c5f7;
    --warning-color: #ffaa44;
    --danger-color: #f85149;
    
    /* Text Colors */
    --text-primary: #f6f8fa;
    --text-secondary: #8c949d;
    --text-muted: #656d76;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--accent-primary), #7b68ee);
    
    /* Fonts */
    --font-primary: 'Inter', system-ui, sans-serif;
    --font-mono: 'Space Mono', monospace;
    
    /* Spacing */
    --sidebar-width: 280px;
    --topbar-height: 64px;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.4);
}

/* ===== RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-primary);
    background: var(--primary-bg);
    color: var(--text-primary);
    overflow-x: hidden;
}

/* ===== LAYOUT ===== */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 1000;
    transition: transform 0.3s ease;
}

.main-content {
    margin-left: var(--sidebar-width);
    min-height: 100vh;
    transition: margin-left 0.3s ease;
}

/* ===== SIDEBAR ===== */
.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 12px;
}

.sidebar-logo {
    width: 32px;
    height: 32px;
}

.sidebar-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.sidebar-nav {
    flex: 1;
    padding: 20px 0;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.2s ease;
    position: relative;
}

.nav-item:hover {
    background: var(--hover-bg);
    color: var(--text-primary);
    text-decoration: none;
}

.nav-item.active {
    background: rgba(98, 100, 167, 0.1);
    color: var(--accent-primary);
    border-right: 3px solid var(--accent-primary);
}

.nav-item i {
    width: 20px;
    font-size: 1.1rem;
}

.badge {
    background: var(--danger-color);
    color: white;
    font-size: 0.75rem;
    padding: 2px 6px;
    border-radius: 10px;
    margin-left: auto;
}

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

.user-profile {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px;
    border-radius: 8px;
    transition: background 0.2s ease;
}

.user-profile:hover {
    background: var(--hover-bg);
}

.user-avatar {
    width: 36px;
    height: 36px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    color: white;
    font-size: 0.9rem;
}

.user-avatar.small {
    width: 28px;
    height: 28px;
    font-size: 0.8rem;
}

.user-avatar.mini {
    width: 24px;
    height: 24px;
    font-size: 0.7rem;
}

.user-info {
    flex: 1;
}

.user-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}

.user-role {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.user-menu-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: all 0.2s ease;
}

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

/* ===== TOP BAR ===== */
.top-bar {
    height: var(--topbar-height);
    background: var(--secondary-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.top-bar-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.sidebar-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 8px;
    border-radius: 4px;
    transition: all 0.2s ease;
}

.sidebar-toggle:hover {
    background: var(--hover-bg);
    color: var(--text-primary);
}

.page-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.top-bar-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.search-box {
    position: relative;
    width: 300px;
}

.search-box i {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
}

.search-box input {
    width: 100%;
    padding: 8px 12px 8px 36px;
    background: var(--primary-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(98, 100, 167, 0.1);
}

.search-box input::placeholder {
    color: var(--text-muted);
}

.notification-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 8px;
    border-radius: 4px;
    position: relative;
    transition: all 0.2s ease;
}

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

.notification-dot {
    position: absolute;
    top: 6px;
    right: 6px;
    width: 8px;
    height: 8px;
    background: var(--danger-color);
    border-radius: 50%;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 6px;
    transition: background 0.2s ease;
}

.user-menu:hover {
    background: var(--hover-bg);
}

.user-menu i {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

/* ===== DASHBOARD CONTENT ===== */
.dashboard-content {
    padding: 24px;
}

.welcome-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.welcome-content h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.welcome-content p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.quick-actions {
    display: flex;
    gap: 12px;
}

.quick-action-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--accent-primary);
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
}

.quick-action-btn:hover {
    background: var(--accent-secondary);
    transform: translateY(-1px);
}

/* ===== DASHBOARD GRID ===== */
.dashboard-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 24px;
}

.dashboard-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    transition: all 0.2s ease;
}

.dashboard-card:hover {
    box-shadow: var(--shadow-md);
}

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

.card-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.date {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.progress-summary {
    color: var(--success-color);
    font-weight: 600;
}

.assignment-count {
    color: var(--warning-color);
    font-weight: 600;
}

/* ===== SCHEDULE CARD ===== */
.schedule-card {
    grid-column: 1 / -1;
}

.schedule-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.schedule-item {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 16px;
    background: var(--secondary-bg);
    border-radius: 8px;
    border-left: 4px solid transparent;
    transition: all 0.2s ease;
}

.schedule-item:hover {
    background: var(--hover-bg);
}

.schedule-item.current {
    border-left-color: var(--accent-primary);
    background: rgba(98, 100, 167, 0.05);
}

.schedule-time {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 80px;
}

.time {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1rem;
}

.duration {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.schedule-details {
    flex: 1;
}

.schedule-details h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.schedule-details p {
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.schedule-tags {
    display: flex;
    gap: 8px;
}

.tag {
    background: rgba(98, 100, 167, 0.2);
    color: var(--accent-primary);
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
}

.btn-join {
    background: var(--accent-primary);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
}

.btn-join:hover {
    background: var(--accent-secondary);
}

.btn-join.disabled {
    background: var(--hover-bg);
    color: var(--text-secondary);
    cursor: not-allowed;
}

.view-all-link {
    display: inline-flex;
    align-items: center;
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 500;
    margin-top: 16px;
    transition: color 0.2s ease;
}

.view-all-link:hover {
    color: var(--text-primary);
    text-decoration: none;
}

/* ===== PROGRESS CARD ===== */
.progress-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.progress-item {
    display: flex;
    align-items: center;
    gap: 16px;
}

.progress-info {
    flex: 1;
}

.progress-info h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.progress-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.progress-bar {
    flex: 2;
    height: 8px;
    background: var(--hover-bg);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 4px;
    transition: width 0.3s ease;
}

.progress-fill[data-progress="80"] { width: 80%; }
.progress-fill[data-progress="42"] { width: 42%; }
.progress-fill[data-progress="88"] { width: 88%; }

.progress-percent {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    min-width: 40px;
    text-align: right;
}

/* ===== ASSIGNMENTS CARD ===== */
.assignments-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.assignment-item {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding: 16px;
    background: var(--secondary-bg);
    border-radius: 8px;
    border-left: 4px solid transparent;
}

.assignment-item.urgent {
    border-left-color: var(--danger-color);
    background: rgba(248, 81, 73, 0.05);
}

.assignment-info h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.assignment-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.assignment-meta {
    display: flex;
    gap: 12px;
    font-size: 0.8rem;
}

.due-date {
    color: var(--warning-color);
    font-weight: 500;
}

.assignment-type {
    color: var(--text-secondary);
}

.submit-btn {
    background: var(--success-color);
    color: var(--primary-bg);
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
}

.submit-btn:hover {
    background: #a8d3f7;
}

/* ===== ACTIVITY CARD ===== */
.activity-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.activity-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--secondary-bg);
    border-radius: 8px;
}

.activity-icon {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    color: white;
}

.activity-icon.grade { background: #ffd700; }
.activity-icon.message { background: var(--accent-primary); }
.activity-icon.class { background: var(--success-color); }
.activity-icon.achievement { background: #ff6b35; }

.activity-content {
    flex: 1;
}

.activity-content p {
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.activity-time {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.activity-grade {
    font-weight: 700;
    color: #ffd700;
    font-size: 1.1rem;
}

/* ===== STATS CARD ===== */
.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: var(--secondary-bg);
    border-radius: 8px;
}

.stat-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.stat-content {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* ===== COMMUNITY CARD ===== */
.community-posts {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.community-post {
    padding: 16px;
    background: var(--secondary-bg);
    border-radius: 8px;
}

.post-author {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
}

.author-info {
    display: flex;
    flex-direction: column;
}

.author-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}

.post-time {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.post-content {
    font-size: 0.9rem;
    color: var(--text-primary);
    line-height: 1.5;
    margin-bottom: 12px;
}

.post-actions {
    display: flex;
    gap: 16px;
}

.post-action {
    display: flex;
    align-items: center;
    gap: 4px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.8rem;
    transition: color 0.2s ease;
}

.post-action:hover {
    color: var(--accent-primary);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 1200px) {
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .sidebar-toggle {
        display: block;
    }
    
    .search-box {
        width: 200px;
    }
    
    .welcome-section {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }
    
    .quick-actions {
        width: 100%;
        justify-content: center;
    }
    
    .dashboard-content {
        padding: 16px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .schedule-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
    
    .schedule-time {
        flex-direction: row;
        align-items: center;
        gap: 8px;
        min-width: auto;
    }
    
    .assignment-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
}

@media (max-width: 480px) {
    .top-bar {
        padding: 0 16px;
    }
    
    .search-box {
        width: 150px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .quick-action-btn {
        width: 100%;
        justify-content: center;
    }
}