:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #10b981;
    --secondary-dark: #059669;
    --danger: #ef4444;
    --warning: #f59e0b;
    --dark: #1e293b;
    --darker: #0f172a;
    --light: #f1f5f9;
    --white: #ffffff;
    --gray: #64748b;
    --border: #e2e8f0;
    --shadow: 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);
    --radius: 12px;
    --radius-sm: 8px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--dark) 0%, var(--darker) 100%);
    min-height: 100vh;
    color: var(--dark);
}

/* Landing Page */
.landing-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.landing-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 50px;
    text-align: center;
    box-shadow: var(--shadow-lg);
    max-width: 500px;
    width: 100%;
}

.landing-icon {
    font-size: 64px;
    margin-bottom: 20px;
}

.landing-card h1 {
    color: var(--dark);
    margin-bottom: 10px;
    font-size: 1.8rem;
}

.landing-card p {
    color: var(--gray);
    margin-bottom: 30px;
}

.landing-buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.btn {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 18px 25px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-icon {
    font-size: 28px;
}

.btn-text {
    text-align: left;
}

.btn-text strong {
    display: block;
    font-size: 1.1rem;
}

.btn-text small {
    opacity: 0.8;
    font-size: 0.85rem;
}

.btn-admin {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: var(--white);
}

.btn-admin:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(37, 99, 235, 0.4);
}

.btn-teacher {
    background: linear-gradient(135deg, var(--secondary) 0%, var(--secondary-dark) 100%);
    color: var(--white);
}

.btn-teacher:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(16, 185, 129, 0.4);
}

.landing-footer {
    margin-top: 30px;
    color: var(--gray);
    font-size: 0.9rem;
}

/* Panel Layout */
.panel-container {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 260px;
    background: var(--darker);
    padding: 30px 20px;
    color: var(--white);
}

.sidebar-logo {
    font-size: 24px;
    font-weight: bold;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.sidebar-subtitle {
    color: var(--gray);
    font-size: 0.85rem;
    margin-bottom: 40px;
}

.sidebar-menu {
    list-style: none;
}

.sidebar-menu li {
    margin-bottom: 8px;
}

.sidebar-menu a {
    color: var(--light);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 15px;
    border-radius: var(--radius-sm);
    transition: all 0.3s ease;
}

.sidebar-menu a:hover,
.sidebar-menu a.active {
    background: rgba(255, 255, 255, 0.1);
    color: var(--white);
}

.sidebar-menu a.logout {
    color: var(--danger);
    margin-top: 30px;
}

.main-content {
    flex: 1;
    background: var(--light);
    padding: 30px;
    overflow-y: auto;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.page-title {
    font-size: 1.8rem;
    color: var(--dark);
}

/* Cards */
.card {
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 25px;
    margin-bottom: 25px;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
}

.card-title {
    font-size: 1.2rem;
    color: var(--dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Tables */
.table-container {
    overflow-x: auto;
}

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

th,
td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    background: var(--light);
    font-weight: 600;
    color: var(--dark);
    font-size: 0.9rem;
    text-transform: uppercase;
}

tr:hover {
    background: rgba(0, 0, 0, 0.02);
}

/* Checkboxes */
.status-checkbox {
    width: 24px;
    height: 24px;
    border-radius: 6px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.status-checkbox.checked {
    background: var(--secondary);
    color: var(--white);
}

.status-checkbox.unchecked {
    background: var(--border);
    color: var(--gray);
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

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

.form-input,
.form-select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary);
}

.form-file {
    padding: 10px;
    background: var(--light);
    border: 2px dashed var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
}

/* Buttons */
.btn-primary {
    background: var(--primary);
    color: var(--white);
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.btn-secondary {
    background: var(--secondary);
    color: var(--white);
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.btn-sm {
    padding: 8px 16px;
    font-size: 0.85rem;
}

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

/* Login Page */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.login-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 40px;
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-lg);
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-icon {
    font-size: 48px;
    margin-bottom: 15px;
}

.login-title {
    font-size: 1.5rem;
    color: var(--dark);
    margin-bottom: 5px;
}

.login-subtitle {
    color: var(--gray);
}

/* Alerts */
.alert {
    padding: 15px 20px;
    border-radius: var(--radius-sm);
    margin-bottom: 20px;
}

.alert-success {
    background: #d1fae5;
    color: #065f46;
    border-left: 4px solid var(--secondary);
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border-left: 4px solid var(--danger);
}

.alert-info {
    background: #dbeafe;
    color: #1e40af;
    border-left: 4px solid var(--primary);
}

/* Tabs */
.tabs {
    display: flex;
    gap: 5px;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border);
    padding-bottom: 0;
}

.tab {
    padding: 12px 20px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    color: var(--gray);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all 0.3s ease;
}

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

.tab.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
    font-weight: 600;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Upload Box */
.upload-box {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 40px;
    text-align: center;
    background: var(--light);
    transition: all 0.3s ease;
}

.upload-box:hover {
    border-color: var(--primary);
    background: #eff6ff;
}

.upload-box-icon {
    font-size: 48px;
    margin-bottom: 15px;
}

.upload-box input[type="file"] {
    display: none;
}

.upload-box label {
    cursor: pointer;
}

/* Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 25px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 20px;
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
}

.stat-icon.blue {
    background: #dbeafe;
}

.stat-icon.green {
    background: #d1fae5;
}

.stat-icon.yellow {
    background: #fef3c7;
}

.stat-icon.red {
    background: #fee2e2;
}

.stat-icon.gray {
    background: #e2e8f0;
}

.stat-icon.purple {
    background: #ede9fe;
}

.stat-info h3 {
    font-size: 1.8rem;
    color: var(--dark);
}

.stat-info p {
    color: var(--gray);
    font-size: 0.9rem;
}

/* Download Link */
.download-link {
    color: var(--primary);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.download-link:hover {
    text-decoration: underline;
}

/* Camera/Scan Button */
.btn-camera {
    background: linear-gradient(135deg, var(--warning) 0%, #d97706 100%);
    color: var(--white);
}

.btn-camera:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(245, 158, 11, 0.4);
}

.upload-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 15px;
}

/* Responsive - Mobile First */
@media (max-width: 480px) {
    .landing-card {
        padding: 25px 20px;
    }

    .landing-card h1 {
        font-size: 1.4rem;
    }

    .landing-icon {
        font-size: 48px;
    }

    .btn {
        padding: 14px 18px;
        font-size: 0.95rem;
    }

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

    .main-content {
        padding: 15px;
    }

    .page-title {
        font-size: 1.3rem;
    }

    .card {
        padding: 15px;
    }

    .card-title {
        font-size: 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .stat-card {
        padding: 15px;
    }

    .stat-icon {
        width: 45px;
        height: 45px;
        font-size: 22px;
    }

    .stat-info h3 {
        font-size: 1.4rem;
    }

    .tabs {
        flex-wrap: wrap;
        gap: 5px;
    }

    .tab {
        padding: 10px 12px;
        font-size: 0.85rem;
        flex: 1;
        min-width: 45%;
        text-align: center;
    }

    .upload-box {
        padding: 25px 15px;
    }

    .upload-box-icon {
        font-size: 36px;
    }

    th,
    td {
        padding: 10px 8px;
        font-size: 0.85rem;
    }

    .form-input,
    .form-select {
        padding: 10px 12px;
        font-size: 16px;
        /* Prevents zoom on iOS */
    }

    .btn-primary,
    .btn-secondary {
        padding: 12px 18px;
        font-size: 1rem;
        width: 100%;
    }

    .upload-buttons {
        flex-direction: column;
    }

    .upload-buttons .btn {
        width: 100%;
        justify-content: center;
    }

    .filter-form {
        flex-direction: column;
        align-items: stretch !important;
        gap: 10px !important;
    }

    .filter-form label {
        margin-left: 0 !important;
    }

    .filter-form select,
    .filter-form input {
        width: 100% !important;
    }

    .filter-form .btn {
        width: 100%;
    }
}

@media (max-width: 768px) {
    .panel-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        padding: 15px;
        position: sticky;
        top: 0;
        z-index: 100;
    }

    .sidebar-logo {
        font-size: 18px;
    }

    .sidebar-subtitle {
        margin-bottom: 15px;
        font-size: 0.8rem;
    }

    .sidebar-menu {
        display: flex;
        flex-wrap: wrap;
        gap: 8px;
    }

    .sidebar-menu li {
        margin-bottom: 0;
    }

    .sidebar-menu a {
        padding: 10px 14px;
        font-size: 0.9rem;
    }

    .sidebar-menu a.logout {
        margin-top: 0;
    }

    .main-content {
        padding: 20px;
    }

    .landing-card {
        padding: 30px;
    }

    .page-header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .card-header {
        flex-direction: column;
        gap: 10px;
        align-items: flex-start;
    }

    /* Weekly plans grid mobile */
    .teacher-name {
        min-width: 120px !important;
        max-width: 120px !important;
        font-size: 0.8rem;
        padding: 8px !important;
    }

    .week-col {
        min-width: 50px !important;
    }

    .week-header {
        font-size: 0.6rem !important;
        padding: 6px 2px !important;
    }

    .week-num {
        font-size: 0.75rem !important;
    }

    .week-cell {
        padding: 6px 2px !important;
        min-height: 28px !important;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .sidebar {
        width: 220px;
    }

    .main-content {
        padding: 25px;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1025px) {
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* Touch improvements */
@media (hover: none) and (pointer: coarse) {

    .btn,
    .tab,
    .sidebar-menu a {
        min-height: 44px;
    }

    .form-input,
    .form-select {
        min-height: 48px;
    }
}

/* Print styles */
@media print {
    .sidebar {
        display: none;
    }

    .main-content {
        padding: 0;
    }

    .btn {
        display: none;
    }
}