:root {
    --bg-gradient: radial-gradient(circle at 10% 20%, rgba(244, 246, 250, 1) 0%, rgba(232, 238, 248, 1) 90%);
    --panel-bg: rgba(255, 255, 255, 0.75);
    --panel-border: rgba(218, 226, 237, 0.8);
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: rgba(37, 99, 235, 0.1);
    --whatsapp-green: #25d366;
    --whatsapp-dark: #075e54;
    --whatsapp-light: #dcf8c6;
    --danger: #ef4444;
    --success: #10b981;
    --warning: #f59e0b;
    --shadow-sm: 0 1px 2px 0 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);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --border-radius: 16px;
    --font-sans: 'Outfit', 'Inter', system-ui, -apple-system, sans-serif;
    --glass-blur: blur(12px);
}

[data-theme="dark"] {
    --bg-gradient: radial-gradient(circle at 10% 20%, rgba(15, 22, 36, 1) 0%, rgba(9, 13, 22, 1) 90%);
    --panel-bg: rgba(22, 30, 49, 0.75);
    --panel-border: rgba(38, 48, 71, 0.8);
    --card-bg: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --accent-light: rgba(59, 130, 246, 0.15);
    --whatsapp-green: #25d366;
    --whatsapp-dark: #128c7e;
    --whatsapp-light: #054740;
    --danger: #f87171;
    --success: #34d399;
    --warning: #fbbf24;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    transition: background-color 0.3s ease, border-color 0.3s ease, color 0.2s ease;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-gradient);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 2rem 1rem;
    line-height: 1.5;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
}

/* Header Section */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding: 0 0.5rem;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.brand-icon {
    font-size: 2.2rem;
    background: linear-gradient(135deg, var(--accent), var(--whatsapp-green));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-title h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-title p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.theme-toggle {
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    color: var(--text-primary);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
    backdrop-filter: var(--glass-blur);
}

.theme-toggle:hover {
    transform: scale(1.05);
}

.theme-toggle i {
    font-size: 1.2rem;
}

/* Config / Input Panel */
.config-card {
    background: var(--panel-bg);
    backdrop-filter: var(--glass-blur);
    border: 1px solid var(--panel-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-md);
}

.config-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.25rem;
}

@media(min-width: 768px) {
    .config-grid {
        grid-template-columns: 2fr 1fr 1fr;
    }
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-wrapper i {
    position: absolute;
    left: 1rem;
    color: var(--text-muted);
}

.input-wrapper input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.5rem;
    border: 1px solid var(--panel-border);
    border-radius: 10px;
    background: var(--card-bg);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    box-shadow: var(--shadow-sm);
}

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

.btn-fetch {
    background: linear-gradient(135deg, var(--accent), var(--accent-hover));
    color: white;
    border: none;
    border-radius: 10px;
    padding: 0.75rem 1.5rem;
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    box-shadow: var(--shadow-sm);
    align-self: flex-end;
    height: 46px;
}

.btn-fetch:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-fetch:active {
    transform: translateY(1px);
}

/* Two Column Main Content Area */
.app-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}

@media(min-width: 1024px) {
    .app-content {
        grid-template-columns: 1.2fr 0.8fr;
    }
}

/* Left Column - Report View */
.report-view-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.section-card {
    background: var(--panel-bg);
    backdrop-filter: var(--glass-blur);
    border: 1px solid var(--panel-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--panel-border);
    padding-bottom: 0.75rem;
    margin-bottom: 1.25rem;
}

.section-header h2 {
    font-size: 1.15rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.section-header h2 i {
    color: var(--accent);
}

/* Report Header Details */
.report-meta-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

@media(min-width: 640px) {
    .report-meta-grid {
        grid-template-columns: 1fr 2fr;
    }
}

.meta-item {
    background: var(--card-bg);
    border: 1px solid var(--panel-border);
    padding: 1rem;
    border-radius: 12px;
}

.meta-item label {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    display: block;
    margin-bottom: 0.25rem;
}

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

.absentee-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.absentee-badge {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
    border: 1px solid rgba(239, 68, 68, 0.2);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.85rem;
    font-weight: 500;
}

.no-absentees {
    color: var(--success);
    font-size: 0.9rem;
    font-weight: 500;
}

/* Assignment Grid & Books Grid */
.grid-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

@media(min-width: 640px) {
    .grid-list {
        grid-template-columns: repeat(2, 1fr);
    }
}

.subject-item-card {
    background: var(--card-bg);
    border: 1px solid var(--panel-border);
    border-left: 4px solid var(--accent);
    padding: 1rem;
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.subject-item-card.has-content {
    border-left-color: var(--success);
    background: rgba(16, 185, 129, 0.09);
    border-color: rgba(16, 185, 129, 0.3);
    box-shadow: 0 4px 12px -2px rgba(16, 185, 129, 0.1);
}

[data-theme="dark"] .subject-item-card.has-content {
    background: rgba(52, 211, 153, 0.14);
    border-color: rgba(52, 211, 153, 0.35);
    box-shadow: 0 4px 12px -2px rgba(0, 0, 0, 0.2);
}

.subject-item-card.has-books-content {
    border-left-color: var(--warning);
    background: rgba(245, 158, 11, 0.09);
    border-color: rgba(245, 158, 11, 0.3);
    box-shadow: 0 4px 12px -2px rgba(245, 158, 11, 0.1);
}

[data-theme="dark"] .subject-item-card.has-books-content {
    background: rgba(251, 191, 36, 0.14);
    border-color: rgba(251, 191, 36, 0.35);
    box-shadow: 0 4px 12px -2px rgba(0, 0, 0, 0.2);
}

.subject-item-card.no-content {
    border-left-color: var(--text-muted);
    opacity: 0.7;
}

.subject-item-card h4 {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--text-primary);
}

.subject-item-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.subject-item-card .empty-text {
    font-style: italic;
    color: var(--text-muted);
}

/* Classroom Activity Table & Cards */
.activity-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.activity-card {
    background: var(--card-bg);
    border: 1px solid var(--panel-border);
    border-radius: 12px;
    overflow: hidden;
}

.activity-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    background: rgba(0, 0, 0, 0.02);
    border-bottom: 1px solid var(--panel-border);
}

[data-theme="dark"] .activity-card-header {
    background: rgba(255, 255, 255, 0.02);
}

.activity-subject-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.activity-subject-name {
    font-weight: 700;
    font-size: 1rem;
}

.session-badge {
    padding: 0.2rem 0.5rem;
    font-size: 0.75rem;
    font-weight: 700;
    border-radius: 4px;
    text-transform: uppercase;
}

.session-badge.yes {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success);
}

.session-badge.no {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
}

.activity-card-body {
    padding: 1rem;
}

.activity-meta-row {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 0.75rem;
}

.activity-meta-tag {
    background: var(--bg-gradient);
    border: 1px solid var(--panel-border);
    padding: 0.25rem 0.6rem;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 500;
}

.activity-meta-tag strong {
    font-weight: 600;
    color: var(--text-secondary);
}

.activity-description {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-primary);
}

/* Right Column - WhatsApp Bubble Simulator */
.whatsapp-panel {
    background: var(--panel-bg);
    backdrop-filter: var(--glass-blur);
    border: 1px solid var(--panel-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    position: sticky;
    top: 2rem;
}

.simulator-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.simulator-title {
    font-size: 1.1rem;
    font-weight: 700;
}

/* WhatsApp Phone Frame Simulator */
.phone-mockup {
    background-color: #efeae2;
    background-image: url('https://user-images.githubusercontent.com/15075759/28719144-86dc0f70-73b1-11e7-911d-60d70fcded21.png'); /* Classic WhatsApp Background */
    border-radius: 20px;
    border: 8px solid #333;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    aspect-ratio: 9/16;
    max-height: 620px;
    width: 100%;
    margin: 0 auto;
}

[data-theme="dark"] .phone-mockup {
    background-color: #0b141a;
    background-image: url('https://user-images.githubusercontent.com/15075759/143831899-73f1d82f-ed3b-48c0-bc66-3d75fb432168.png'); /* Classic WhatsApp Dark Background */
    border-color: #222;
}

.phone-header {
    background: #075e54;
    color: white;
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

[data-theme="dark"] .phone-header {
    background: #1f2c34;
}

.phone-avatar {
    width: 38px;
    height: 38px;
    border-radius: 50%;
    background: #ccc;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.phone-contact-info {
    flex-grow: 1;
}

.phone-contact-name {
    font-weight: 600;
    font-size: 0.95rem;
    line-height: 1.2;
}

.phone-contact-status {
    font-size: 0.75rem;
    opacity: 0.8;
}

.phone-header-actions {
    display: flex;
    gap: 1rem;
    font-size: 1.1rem;
}

.chat-area {
    flex-grow: 1;
    padding: 1rem;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

.message-bubble {
    background: #ffffff;
    color: #303030;
    border-radius: 8px 8px 8px 0;
    padding: 0.75rem;
    max-width: 85%;
    align-self: flex-start;
    box-shadow: 0 1px 0.5px rgba(0, 0, 0, 0.13);
    position: relative;
    font-size: 0.85rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    width: 100%;
}

[data-theme="dark"] .message-bubble {
    background: #202c33;
    color: #e9edef;
}

.message-bubble-textarea {
    width: 100%;
    min-height: 250px;
    border: none;
    background: transparent;
    color: inherit;
    font-family: inherit;
    font-size: 0.85rem;
    resize: none;
    line-height: 1.5;
    outline: none;
}

.message-bubble-footer {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.7rem;
    color: #8696a0;
}

.message-bubble-footer i {
    color: #53bdeb; /* Double blue ticks */
}

/* Panel actions under simulator */
.panel-actions {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.btn-send-wa {
    background: var(--whatsapp-green);
    color: white;
    border: none;
    border-radius: 10px;
    padding: 0.85rem 1.5rem;
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    box-shadow: var(--shadow-md);
    text-decoration: none;
}

.btn-send-wa:hover {
    background: #20ba5a;
    transform: translateY(-1px);
}

.btn-copy-wa {
    background: var(--card-bg);
    color: var(--text-primary);
    border: 1px solid var(--panel-border);
    border-radius: 10px;
    padding: 0.85rem 1.5rem;
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    box-shadow: var(--shadow-sm);
}

.btn-copy-wa:hover {
    background: var(--panel-border);
}

/* Skeleton Loaders */
.skeleton {
    animation: skeleton-loading 1.5s infinite alternate;
}

@keyframes skeleton-loading {
    0% {
        background-color: var(--panel-border);
        opacity: 0.6;
    }
    100% {
        background-color: var(--panel-border);
        opacity: 1;
    }
}

.skeleton-title {
    height: 1.5rem;
    width: 200px;
    border-radius: 4px;
    margin-bottom: 1rem;
}

.skeleton-meta {
    height: 3rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.skeleton-card {
    height: 5rem;
    border-radius: 12px;
    margin-bottom: 1rem;
}

/* Utility classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.empty-state {
    padding: 4rem 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 3.5rem;
    background: linear-gradient(135deg, var(--text-muted), var(--panel-border));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.empty-state h3 {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-primary);
}

/* Alerts and toasts */
.alert-box {
    padding: 1rem;
    border-radius: 10px;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    font-size: 0.95rem;
}

.alert-box.danger {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.2);
    color: var(--danger);
}

.alert-box i {
    margin-top: 0.15rem;
}

/* Toast Notifications */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: #333;
    color: #fff;
    padding: 0.75rem 1.5rem;
    border-radius: 30px;
    font-size: 0.9rem;
    font-weight: 600;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    z-index: 9999;
    opacity: 0;
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275), opacity 0.3s ease;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.toast.success {
    background: var(--success);
}

/* Activity Table compact styles */
.activity-table-wrapper {
    overflow-x: auto;
    border: 1px solid var(--panel-border);
    border-radius: 12px;
    background: var(--card-bg);
}

.activity-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    text-align: left;
}

.activity-table th {
    background: rgba(0, 0, 0, 0.02);
    padding: 0.75rem 1rem;
    font-weight: 700;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--panel-border);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

[data-theme="dark"] .activity-table th {
    background: rgba(255, 255, 255, 0.02);
}

.activity-table td {
    padding: 0.75rem 1rem;
    vertical-align: top;
    border-bottom: 1px solid var(--panel-border);
}

.activity-table tr:last-child td {
    border-bottom: none;
}

.activity-table-subject {
    font-weight: 700;
    color: var(--text-primary);
    text-transform: uppercase;
}

.activity-table-meta {
    font-size: 0.75rem;
    color: var(--accent);
    margin-top: 0.25rem;
    display: block;
    font-weight: 600;
}

.activity-table-desc {
    color: var(--text-primary);
    line-height: 1.55;
}

.no-sessions-row {
    margin-top: 1.25rem;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.no-sessions-badge {
    background: rgba(0, 0, 0, 0.03);
    border: 1px solid var(--panel-border);
    color: var(--text-secondary);
    padding: 0.15rem 0.5rem;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
}

[data-theme="dark"] .no-sessions-badge {
    background: rgba(255, 255, 255, 0.03);
}