:root {
    --primary: #4a6bff;
    --primary-dark: #3a56d4;
    --primary-light: #6c8aff;
    --secondary: #ff6b9d;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #06b6d4;
    
    --dark: #1e293b;
    --darker: #0f172a;
    --light: #f8fafc;
    --lighter: #ffffff;
    --gray: #64748b;
    --gray-light: #e2e8f0;
    --gray-dark: #475569;
    
    --gradient-primary: linear-gradient(135deg, #4a6bff 0%, #6c8aff 100%);
    --gradient-success: linear-gradient(135deg, #10b981 0%, #34d399 100%);
    --gradient-warning: linear-gradient(135deg, #f59e0b 0%, #fbbf24 100%);
    --gradient-danger: linear-gradient(135deg, #ef4444 0%, #f87171 100%);
    
    --border-radius: 12px;
    --border-radius-lg: 20px;
    --border-radius-sm: 8px;
    
    --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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    color: var(--dark);
    transition: var(--transition);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

body.dark-mode {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: #e2e8f0;
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* Animated Header */
.animated-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding: 20px;
    background: var(--lighter);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    animation: slideDown 0.6s ease-out;
    position: relative;
    overflow: hidden;
}

.animated-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 3px;
    background: var(--gradient-primary);
    animation: shimmer 3s infinite;
}

.dark-mode .animated-header {
    background: var(--darker);
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.logo i {
    font-size: 32px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: bounce 2s infinite;
}

.badge {
    background: var(--gradient-danger);
    color: white;
    padding: 4px 8px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

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

.stat-card {
    background: var(--lighter);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 15px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--gradient-primary);
}

.stat-card:nth-child(2)::before { background: var(--gradient-success); }
.stat-card:nth-child(3)::before { background: var(--gradient-warning); }
.stat-card:nth-child(4)::before { background: var(--gradient-danger); }

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.dark-mode .stat-card {
    background: var(--dark);
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    color: white;
    font-size: 24px;
}

.stat-card:nth-child(2) .stat-icon { background: var(--gradient-success); }
.stat-card:nth-child(3) .stat-icon { background: var(--gradient-warning); }
.stat-card:nth-child(4) .stat-icon { background: var(--gradient-danger); }

.stat-info h3 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 5px;
}

.stat-info p {
    color: var(--gray);
    font-size: 14px;
}

.dark-mode .stat-info p {
    color: var(--gray-light);
}

/* Tool Grid */
.tool-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

@media (max-width: 1024px) {
    .tool-grid {
        grid-template-columns: 1fr;
    }
}

/* Cards */
.card {
    background: var(--lighter);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
    padding: 30px;
    margin-bottom: 25px;
    transition: var(--transition);
    border: 1px solid transparent;
}

.card:hover {
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-light);
}

.dark-mode .card {
    background: var(--dark);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--gray-light);
}

.dark-mode .card-header {
    border-bottom-color: var(--gray-dark);
}

.card-header h2 {
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 22px;
}

.card-header h2 i {
    font-size: 24px;
}

.word-count {
    color: var(--gray);
    font-size: 14px;
}

.dark-mode .word-count {
    color: var(--gray-light);
}

/* Status Badges */
.status-badge, .quality-badge {
    background: var(--gradient-success);
    color: white;
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 5px;
}

.quality-badge {
    background: var(--gradient-warning);
}

/* Text Areas */
textarea {
    width: 100%;
    min-height: 300px;
    padding: 20px;
    border: 2px solid var(--gray-light);
    border-radius: var(--border-radius);
    resize: vertical;
    font-size: 16px;
    line-height: 1.6;
    transition: var(--transition);
    background: var(--lighter);
}

.dark-mode textarea {
    background: var(--darker);
    color: #e2e8f0;
    border-color: var(--gray-dark);
}

textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(74, 107, 255, 0.1);
}

/* Buttons */
.btn-group {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transition: var(--transition);
    transform: translate(-50%, -50%);
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn:active {
    transform: translateY(0);
}

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

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

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

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

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
}

.dark-mode .btn-outline {
    color: #e2e8f0;
    border-color: #e2e8f0;
}

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

.btn-icon {
    padding: 10px;
    border: none;
    border-radius: var(--border-radius-sm);
    background: transparent;
    color: var(--gray);
    cursor: pointer;
    transition: var(--transition);
}

.btn-icon:hover {
    background: var(--gray-light);
    color: var(--primary);
}

.dark-mode .btn-icon:hover {
    background: var(--gray-dark);
}

/* Similarity Score */
.similarity-score {
    display: flex;
    justify-content: center;
    margin: 30px 0;
}

.score-circle {
    position: relative;
    width: 120px;
    height: 120px;
}

.progress-ring {
    transform: rotate(-90deg);
}

.progress-ring-background {
    fill: none;
    stroke: var(--gray-light);
    stroke-width: 8;
}

.dark-mode .progress-ring-background {
    stroke: var(--gray-dark);
}

.progress-ring-circle {
    fill: none;
    stroke: var(--primary);
    stroke-width: 8;
    stroke-dasharray: 339.292;
    stroke-dashoffset: 339.292;
    transition: stroke-dashoffset 1s ease-in-out;
}

.score-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.score-text span {
    font-size: 32px;
    font-weight: 700;
    display: block;
}

.score-text small {
    font-size: 12px;
    color: var(--gray);
}

.dark-mode .score-text small {
    color: var(--gray-light);
}

/* Score Breakdown */
.score-breakdown {
    margin: 25px 0;
}

.breakdown-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.breakdown-item .label {
    flex: 1;
    font-size: 14px;
    color: var(--gray);
}

.dark-mode .breakdown-item .label {
    color: var(--gray-light);
}

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

.dark-mode .progress-bar {
    background: var(--gray-dark);
}

.progress-fill {
    height: 100%;
    background: var(--primary);
    border-radius: 4px;
    transition: width 1s ease-in-out;
    width: 0%;
}

.breakdown-item .value {
    flex: 0 0 40px;
    text-align: right;
    font-weight: 600;
}

/* Highlighted Text */
.highlighted-text, .paraphrased-text {
    background: var(--light);
    padding: 20px;
    border-radius: var(--border-radius);
    line-height: 1.8;
    min-height: 200px;
    border: 1px solid var(--gray-light);
    max-height: 400px;
    overflow-y: auto;
}

.dark-mode .highlighted-text,
.dark-mode .paraphrased-text {
    background: var(--darker);
    border-color: var(--gray-dark);
}

.highlight {
    background: rgba(255, 193, 7, 0.3);
    padding: 2px 4px;
    border-radius: 3px;
    transition: var(--transition);
    cursor: pointer;
}

.highlight:hover {
    background: rgba(255, 193, 7, 0.5);
}

.highlight.plagiarism {
    background: rgba(239, 68, 68, 0.3);
}

.highlight.plagiarism:hover {
    background: rgba(239, 68, 68, 0.5);
}

/* Output Header */
.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--gray-light);
}

.dark-mode .output-header {
    border-bottom-color: var(--gray-dark);
}

.output-stats {
    display: flex;
    gap: 20px;
    font-size: 14px;
    color: var(--gray);
}

.dark-mode .output-stats {
    color: var(--gray-light);
}

.output-stats span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.output-actions {
    display: flex;
    gap: 8px;
}

.output-footer {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    flex-wrap: wrap;
}

.action-buttons {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    flex-wrap: wrap;
}

/* Loading Animation */
.loading {
    display: none;
    text-align: center;
    padding: 40px 20px;
}

.loading-spinner {
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-left-color: var(--primary);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

.dark-mode .loading-spinner {
    border-left-color: var(--primary);
}

/* Settings Panel */
.settings-panel {
    margin-top: 25px;
    padding-top: 25px;
    border-top: 2px solid var(--gray-light);
}

.dark-mode .settings-panel {
    border-top-color: var(--gray-dark);
}

.settings-panel h3 {
    margin-bottom: 20px;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 15px;
}

.setting-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px;
    border-radius: var(--border-radius-sm);
    transition: var(--transition);
}

.setting-item:hover {
    background: var(--gray-light);
}

.dark-mode .setting-item:hover {
    background: var(--gray-dark);
}

/* Toggle Switch */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 24px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--gray);
    transition: .4s;
    border-radius: 24px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--primary);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--lighter);
    border-radius: var(--border-radius-lg);
    padding: 30px;
    max-width: 500px;
    width: 90%;
    box-shadow: var(--shadow-xl);
    animation: modalSlideIn 0.3s ease-out;
}

.dark-mode .modal-content {
    background: var(--dark);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--gray-light);
}

.dark-mode .modal-header {
    border-bottom-color: var(--gray-dark);
}

.close-modal {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--gray);
    transition: var(--transition);
}

.close-modal:hover {
    color: var(--danger);
}

.tone-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.tone-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    padding: 20px;
    border: 2px solid var(--gray-light);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
}

.tone-option:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.tone-option i {
    font-size: 32px;
    color: var(--primary);
}

.tone-option.active {
    border-color: var(--primary);
    background: rgba(74, 107, 255, 0.1);
}

/* Footer */
footer {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 2px solid var(--gray-light);
    text-align: center;
}

.dark-mode footer {
    border-top-color: var(--gray-dark);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 20px;
    text-align: left;
}

.footer-section h4 {
    margin-bottom: 15px;
    color: var(--primary);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--gray-light);
    border-radius: 50%;
    color: var(--dark);
    transition: var(--transition);
}

.dark-mode .social-links a {
    background: var(--gray-dark);
    color: var(--light);
}

.social-links a:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-2px);
}

.copyright {
    color: var(--gray);
    font-size: 14px;
}

.dark-mode .copyright {
    color: var(--gray-light);
}

/* Notification System */
.notification-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1001;
}

.notification {
    padding: 16px 20px;
    background: var(--success);
    color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 12px;
    transform: translateX(150%);
    transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    min-width: 300px;
}

.notification.show {
    transform: translateX(0);
}

.notification.error {
    background: var(--danger);
}

.notification.warning {
    background: var(--warning);
}

.notification.info {
    background: var(--info);
}

/* Header Controls */
.header-controls {
    display: flex;
    gap: 15px;
    align-items: center;
}

.mode-toggle {
    background: var(--gray-light);
    border: none;
    padding: 10px 16px;
    border-radius: var(--border-radius);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
    color: var(--dark);
}

.dark-mode .mode-toggle {
    background: var(--gray-dark);
    color: var(--light);
}

.mode-toggle:hover {
    background: var(--primary);
    color: white;
}

/* API Status Badge */
.api-status {
    position: fixed;
    top: 20px;
    left: 20px;
    background: var(--success);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 6px;
    z-index: 1000;
    box-shadow: var(--shadow);
    animation: pulse 2s infinite;
}

.api-status.error {
    background: var(--danger);
    animation: none;
}

/* Animations */
@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes shimmer {
    0% { left: -100%; }
    100% { left: 100%; }
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translate(-50%, -60%);
    }
    to {
        opacity: 1;
        transform: translate(-50%, -50%);
    }
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(16, 185, 129, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(16, 185, 129, 0);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .animated-header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .dashboard-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .tool-grid {
        gap: 20px;
    }
    
    .card {
        padding: 20px;
    }
    
    .footer-content {
        text-align: center;
    }
    
    .social-links {
        justify-content: center;
    }
    
    .output-header {
        flex-direction: column;
        gap: 15px;
        align-items: flex-start;
    }
    
    .output-footer {
        flex-direction: column;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .tone-options {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .dashboard-stats {
        grid-template-columns: 1fr;
    }
    
    .logo {
        font-size: 24px;
    }
    
    .card-header {
        flex-direction: column;
        gap: 10px;
        align-items: flex-start;
    }
    
    .settings-grid {
        grid-template-columns: 1fr;
    }
}