/* ================================================
   COMPONENT STYLES - Physics LMS
   ================================================ */

/* ---- BUTTONS ---- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: 10px 22px;
    font-family: var(--font-body);
    font-size: var(--fs-sm);
    font-weight: var(--fw-semibold);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    white-space: nowrap;
}

.btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at var(--x, 50%) var(--y, 50%), rgba(255, 255, 255, 0.15) 0%, transparent 60%);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.btn:hover::after {
    opacity: 1;
}

.btn-primary {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: 0 4px 15px var(--accent-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px var(--accent-glow);
}

.btn-secondary {
    background: var(--glass-bg);
    color: var(--neutral-100);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: var(--glass-hover);
    border-color: var(--accent-400);
}

.btn-success {
    background: var(--gradient-success);
    color: var(--white);
}

.btn-danger {
    background: var(--gradient-danger);
    color: var(--white);
}

.btn-ghost {
    background: transparent;
    color: var(--neutral-300);
}

.btn-ghost:hover {
    color: var(--white);
    background: var(--glass-bg);
}

.btn-sm {
    padding: 6px 14px;
    font-size: var(--fs-xs);
}

.btn-lg {
    padding: 14px 32px;
    font-size: var(--fs-md);
}

.btn-block {
    width: 100%;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.btn .spinner {
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

/* ---- INPUTS ---- */
.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.form-label {
    font-size: var(--fs-sm);
    font-weight: var(--fw-medium);
    color: var(--neutral-300);
}

.form-input,
.form-select,
.form-textarea {
    padding: 11px 16px;
    font-family: var(--font-body);
    font-size: var(--fs-base);
    color: var(--white);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    outline: none;
    transition: all var(--transition-base);
    backdrop-filter: blur(10px);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    border-color: var(--accent-400);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.form-input::placeholder {
    color: var(--neutral-500);
}

.form-textarea {
    min-height: 100px;
    resize: vertical;
}

.form-select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%238888a0' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

.form-select option {
    background: var(--neutral-800);
    color: var(--white);
}

.form-error {
    color: var(--error-400);
    font-size: var(--fs-xs);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
}

@media (max-width: 768px) {
    .form-row {
        grid-template-columns: 1fr;
    }
}

/* ---- CARDS ---- */
.card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    backdrop-filter: blur(20px);
    transition: all var(--transition-base);
}

.card:hover {
    border-color: rgba(108, 99, 255, 0.2);
}

.card-gradient {
    background: var(--gradient-card);
    border: 1px solid var(--glass-border);
}

.stat-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    backdrop-filter: blur(20px);
    display: flex;
    align-items: center;
    gap: var(--space-4);
    transition: all var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-glow);
}

.stat-icon {
    width: 52px;
    height: 52px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    flex-shrink: 0;
}

.stat-icon.purple {
    background: rgba(108, 99, 255, 0.15);
    color: var(--accent-400);
}

.stat-icon.cyan {
    background: rgba(0, 212, 255, 0.15);
    color: var(--cyan-500);
}

.stat-icon.green {
    background: var(--success-bg);
    color: var(--success-400);
}

.stat-icon.orange {
    background: var(--warning-bg);
    color: var(--warning-400);
}

.stat-value {
    font-family: var(--font-heading);
    font-size: var(--fs-2xl);
    font-weight: var(--fw-bold);
    color: var(--white);
}

.stat-label {
    font-size: var(--fs-xs);
    color: var(--neutral-400);
    margin-top: 2px;
}

/* ---- SIDEBAR ---- */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--gradient-sidebar);
    border-right: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    z-index: 1000;
    transition: width var(--transition-base);
    overflow-x: hidden;
}

.sidebar.collapsed {
    width: var(--sidebar-collapsed);
    overflow: hidden;
}

.sidebar-header {
    padding: var(--space-6);
    display: flex;
    align-items: center;
    gap: var(--space-3);
    border-bottom: 1px solid var(--glass-border);
    min-height: var(--topbar-height);
}

.sidebar-logo {
    width: 38px;
    height: 38px;
    background: var(--gradient-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.sidebar-brand {
    font-family: var(--font-heading);
    font-size: var(--fs-lg);
    font-weight: var(--fw-bold);
    color: var(--white);
    white-space: nowrap;
    overflow: hidden;
}

.sidebar.collapsed .sidebar-brand {
    display: none;
}

.sidebar-nav {
    flex: 1;
    padding: var(--space-4);
    overflow-y: auto;
}

.nav-section {
    margin-bottom: var(--space-6);
}

.nav-section-title {
    font-size: var(--fs-xs);
    font-weight: var(--fw-semibold);
    color: var(--neutral-500);
    text-transform: uppercase;
    letter-spacing: 1px;
    padding: 0 var(--space-3);
    margin-bottom: var(--space-2);
}

.sidebar.collapsed .nav-section-title {
    display: none;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: 10px var(--space-3);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--neutral-400);
    font-size: var(--fs-sm);
    font-weight: var(--fw-medium);
    position: relative;
    white-space: nowrap;
}

.nav-item:hover {
    color: var(--white);
    background: var(--glass-bg);
}

.nav-item.active {
    color: var(--white);
    background: rgba(108, 99, 255, 0.15);
}

.nav-item.active::before {
    content: '';
    position: absolute;
    left: -16px;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 24px;
    background: var(--accent-400);
    border-radius: 0 4px 4px 0;
}

.nav-icon {
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
    flex-shrink: 0;
}

.sidebar.collapsed .nav-text {
    display: none;
}

.sidebar-footer {
    padding: var(--space-4) var(--space-6);
    border-top: 1px solid var(--glass-border);
}

.sidebar.collapsed .sidebar-footer {
    padding: var(--space-3) var(--space-2);
}

.sidebar.collapsed .sidebar-footer > div:first-child {
    justify-content: center;
    margin-bottom: 4px !important;
}

.sidebar-toggle {
    background: none;
    border: none;
    color: var(--neutral-400);
    cursor: pointer;
    font-size: 1.2rem;
    padding: var(--space-2);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sidebar-toggle:hover {
    color: var(--white);
    background: var(--glass-bg);
}

/* ---- TOPBAR ---- */
.topbar {
    position: fixed;
    top: 0;
    left: var(--sidebar-width);
    right: 0;
    height: var(--topbar-height);
    background: rgba(10, 10, 26, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-8);
    z-index: 900;
    transition: left var(--transition-base);
}

.topbar.expanded {
    left: var(--sidebar-collapsed);
}

.topbar-left {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.topbar-title {
    font-family: var(--font-heading);
    font-size: var(--fs-lg);
    font-weight: var(--fw-semibold);
}

.topbar-right {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.batch-selector {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    padding: 6px 16px;
    font-size: var(--fs-sm);
    color: var(--neutral-200);
}

.batch-selector select {
    background: transparent;
    border: none;
    color: var(--cyan-400);
    font-family: var(--font-body);
    font-weight: var(--fw-semibold);
    font-size: var(--fs-sm);
    outline: none;
    cursor: pointer;
}

.batch-selector select option {
    background: var(--neutral-800);
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: var(--fw-bold);
    font-size: var(--fs-sm);
    cursor: pointer;
    border: 2px solid transparent;
    transition: border-color var(--transition-fast);
}

.user-avatar:hover {
    border-color: var(--accent-400);
}

.user-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}

/* ---- TABLES ---- */
.table-container {
    overflow-x: auto;
    border-radius: var(--radius-lg);
    border: 1px solid var(--glass-border);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th {
    padding: 14px 16px;
    text-align: left;
    font-size: var(--fs-xs);
    font-weight: var(--fw-semibold);
    color: var(--neutral-400);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: rgba(255, 255, 255, 0.03);
    border-bottom: 1px solid var(--glass-border);
    white-space: nowrap;
}

.data-table td {
    padding: 12px 16px;
    font-size: var(--fs-sm);
    border-bottom: 1px solid rgba(255, 255, 255, 0.04);
    vertical-align: middle;
}

.data-table tr:hover td {
    background: rgba(108, 99, 255, 0.04);
}

.data-table tr.highlight td {
    background: rgba(108, 99, 255, 0.08);
}

/* ---- BADGE ---- */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 3px 10px;
    border-radius: var(--radius-full);
    font-size: var(--fs-xs);
    font-weight: var(--fw-semibold);
}

.badge-success {
    background: var(--success-bg);
    color: var(--success-400);
}

.badge-error {
    background: var(--error-bg);
    color: var(--error-400);
}

.badge-warning {
    background: var(--warning-bg);
    color: var(--warning-400);
}

.badge-info {
    background: var(--info-bg);
    color: var(--info-500);
}

.badge-neutral {
    background: rgba(255, 255, 255, 0.06);
    color: var(--neutral-400);
}

/* ---- MODAL ---- */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    animation: fadeIn 0.2s ease;
    padding: var(--space-4);
}

.modal {
    background: var(--neutral-800);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    width: 100%;
    max-width: 560px;
    max-height: 90vh;
    overflow-y: auto;
    animation: scaleIn 0.3s var(--transition-spring);
}

.modal-lg {
    max-width: 800px;
}

.modal-header {
    padding: var(--space-6);
    border-bottom: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-header h3 {
    font-size: var(--fs-xl);
}

.modal-close {
    background: none;
    border: none;
    color: var(--neutral-400);
    font-size: 1.5rem;
    cursor: pointer;
    padding: var(--space-1);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    color: var(--white);
    background: var(--glass-bg);
}

.modal-body {
    padding: var(--space-6);
}

.modal-footer {
    padding: var(--space-4) var(--space-6);
    border-top: 1px solid var(--glass-border);
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
}

/* ---- TABS ---- */
.tabs {
    display: flex;
    gap: var(--space-1);
    padding: 4px;
    background: var(--glass-bg);
    border-radius: var(--radius-md);
    overflow-x: auto;
}

.tab {
    padding: 8px 18px;
    font-size: var(--fs-sm);
    font-weight: var(--fw-medium);
    color: var(--neutral-400);
    border: none;
    background: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    font-family: var(--font-body);
}

.tab:hover {
    color: var(--white);
}

.tab.active {
    color: var(--white);
    background: var(--accent-500);
}

/* ---- FILE UPLOAD ---- */
.file-dropzone {
    border: 2px dashed var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--space-10);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    background: var(--glass-bg);
}

.file-dropzone:hover,
.file-dropzone.dragover {
    border-color: var(--accent-400);
    background: rgba(108, 99, 255, 0.05);
}

.file-dropzone-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-3);
}

.file-dropzone-text {
    color: var(--neutral-300);
    font-size: var(--fs-sm);
}

.file-dropzone-hint {
    color: var(--neutral-500);
    font-size: var(--fs-xs);
    margin-top: var(--space-2);
}

/* ---- STAR RATING ---- */
.star-rating {
    display: inline-flex;
    gap: 2px;
}

.star-rating .star {
    font-size: 1.3rem;
    cursor: pointer;
    color: var(--neutral-600);
    transition: color var(--transition-fast), transform var(--transition-fast);
}

.star-rating .star.filled {
    color: var(--warning-400);
}

.star-rating .star:hover {
    transform: scale(1.2);
}

.star-rating.readonly .star {
    cursor: default;
}

.star-rating.readonly .star:hover {
    transform: none;
}

/* ---- PAGINATION ---- */
.pagination {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    margin-top: var(--space-6);
}

.page-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    background: var(--glass-bg);
    color: var(--neutral-300);
    font-size: var(--fs-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.page-btn:hover {
    border-color: var(--accent-400);
    color: var(--white);
}

.page-btn.active {
    background: var(--accent-500);
    border-color: var(--accent-500);
    color: var(--white);
}

/* ---- SEARCH BAR ---- */
.search-bar {
    position: relative;
    max-width: 360px;
}

.search-bar input {
    width: 100%;
    padding: 10px 16px 10px 40px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    color: var(--white);
    font-family: var(--font-body);
    font-size: var(--fs-sm);
    outline: none;
    transition: all var(--transition-base);
}

.search-bar input:focus {
    border-color: var(--accent-400);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.search-bar input::placeholder {
    color: var(--neutral-500);
}

.search-bar .search-icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--neutral-500);
    font-size: 0.9rem;
}

/* ---- EMPTY STATE ---- */
.empty-state {
    text-align: center;
    padding: var(--space-16) var(--space-8);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: var(--space-4);
    opacity: 0.3;
}

.empty-state-title {
    font-size: var(--fs-xl);
    color: var(--neutral-300);
    margin-bottom: var(--space-2);
}

.empty-state-text {
    color: var(--neutral-500);
    font-size: var(--fs-sm);
    max-width: 400px;
    margin: 0 auto;
}

/* ---- PROGRESS BAR ---- */
.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--glass-bg);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    transition: width var(--transition-base);
}

/* ---- AVATAR ---- */
.avatar {
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--glass-border);
}

.avatar-sm {
    width: 32px;
    height: 32px;
}

.avatar-md {
    width: 44px;
    height: 44px;
}

.avatar-lg {
    width: 64px;
    height: 64px;
}

.avatar-xl {
    width: 80px;
    height: 80px;
}

/* ---- SKELETON LOADER ---- */
.skeleton {
    background: linear-gradient(90deg, var(--glass-bg) 25%, var(--glass-hover) 50%, var(--glass-bg) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: var(--radius-md);
}

.skeleton-text {
    height: 14px;
    margin-bottom: 8px;
}

.skeleton-title {
    height: 24px;
    width: 60%;
    margin-bottom: 12px;
}

.skeleton-avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
}

.skeleton-card {
    height: 120px;
}

/* Mobile sidebar */
.sidebar-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.mobile-open {
        transform: translateX(0);
    }

    .sidebar-backdrop.visible {
        display: block;
    }

    .topbar {
        left: 0;
    }

    .mobile-menu-btn {
        display: flex !important;
    }
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: var(--neutral-300);
    font-size: 1.4rem;
    cursor: pointer;
}