/* Modern Cooper Xiao TODOs - Beautiful Task Manager */

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

:root {
    /* Color Palette */
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #a5b4fc;
    --secondary-color: #f59e0b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;
    
    /* Neutral Colors */
    --white: #ffffff;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    
    /* Spacing */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* Transitions */
    --transition-fast: 0.15s ease-out;
    --transition-normal: 0.3s ease-out;
    --transition-slow: 0.5s ease-out;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--gray-800);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    overflow-x: hidden;
}

/* App Container */
.app-container {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Animated Background */
.background-gradient {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    z-index: -2;
}

.floating-shapes {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.shape {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    animation: float 20s infinite linear;
}

.shape-1 {
    width: 80px;
    height: 80px;
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 120px;
    height: 120px;
    top: 60%;
    right: 10%;
    animation-delay: -7s;
}

.shape-3 {
    width: 60px;
    height: 60px;
    top: 80%;
    left: 20%;
    animation-delay: -14s;
}

.shape-4 {
    width: 100px;
    height: 100px;
    top: 40%;
    right: 30%;
    animation-delay: -21s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px) rotate(0deg);
        opacity: 0.7;
    }
    50% {
        transform: translateY(-20px) rotate(180deg);
        opacity: 1;
    }
}

/* Main Container */
.main-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-6);
    width: 100%;
    z-index: 1;
}

/* Header */
.header {
    margin-bottom: var(--spacing-8);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-6);
}

.logo-section {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
}

.logo-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    animation: pulse 2s infinite;
}

.logo-icon i {
    font-size: var(--font-size-2xl);
    color: var(--white);
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.logo-text h1 {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--white);
    margin-bottom: var(--spacing-1);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.logo-text p {
    color: rgba(255, 255, 255, 0.8);
    font-size: var(--font-size-lg);
    font-weight: 500;
}

.stats-section {
    display: flex;
    gap: var(--spacing-4);
    flex-wrap: wrap;
}

.stat-card {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-xl);
    padding: var(--spacing-4);
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    min-width: 140px;
    transition: var(--transition-normal);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.stat-icon {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-icon i {
    font-size: var(--font-size-lg);
    color: var(--white);
}

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

.stat-number {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--white);
    line-height: 1;
}

.stat-label {
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.8);
    font-weight: 500;
}

/* Sections */
.add-task-section,
.tasks-section {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-8);
    margin-bottom: var(--spacing-6);
    box-shadow: var(--shadow-xl);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-6);
    flex-wrap: wrap;
    gap: var(--spacing-4);
}

.section-header h2 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--gray-800);
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

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

/* Filter Tabs */
.filter-tabs {
    display: flex;
    gap: var(--spacing-2);
    background: var(--gray-100);
    border-radius: var(--radius-lg);
    padding: var(--spacing-1);
}

.filter-btn {
    padding: var(--spacing-2) var(--spacing-4);
    border: none;
    background: transparent;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--gray-600);
    cursor: pointer;
    transition: var(--transition-fast);
}

.filter-btn.active,
.filter-btn:hover {
    background: var(--white);
    color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

/* Task Form */
.task-form {
    margin-top: var(--spacing-6);
}

.form-container {
    display: flex;
    gap: var(--spacing-4);
    align-items: flex-end;
    flex-wrap: wrap;
}

.input-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
    min-width: 300px;
}

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

.input-icon {
    position: absolute;
    left: var(--spacing-4);
    color: var(--gray-400);
    font-size: var(--font-size-lg);
    z-index: 1;
}

.input-wrapper input,
.input-wrapper textarea {
    width: 100%;
    padding: var(--spacing-4) var(--spacing-4) var(--spacing-4) 3rem;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    transition: var(--transition-fast);
    background: var(--white);
}

.input-wrapper input:focus,
.input-wrapper textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.input-wrapper textarea {
    resize: vertical;
    min-height: 60px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-6);
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    font-family: var(--font-family);
    cursor: pointer;
    transition: var(--transition-fast);
    text-decoration: none;
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    box-shadow: var(--shadow-md);
}

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

.btn-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
    border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
    background: var(--gray-200);
}

/* Tasks Container */
.tasks-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
}

.task-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-4);
    padding: var(--spacing-5);
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    transition: var(--transition-normal);
    animation: slideIn 0.3s ease-out;
}

.task-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.task-item.completed {
    background: var(--gray-50);
    border-color: var(--success-color);
}

.task-item.completed .task-title {
    text-decoration: line-through;
    color: var(--gray-500);
}

.task-item.completed .task-description {
    color: var(--gray-400);
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideOut {
    from {
        opacity: 1;
        transform: translateX(0);
    }
    to {
        opacity: 0;
        transform: translateX(-100%);
    }
}

/* Task Checkbox */
.task-checkbox {
    position: relative;
    margin-top: var(--spacing-1);
}

.task-checkbox input[type="checkbox"] {
    width: 20px;
    height: 20px;
    opacity: 0;
    cursor: pointer;
    position: relative;
    z-index: 2;
}

.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    width: 20px;
    height: 20px;
    background: var(--white);
    border: 2px solid var(--gray-300);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    pointer-events: none;
    z-index: 1;
}

.task-checkbox:hover .checkmark {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.1);
}

.checkmark i {
    opacity: 0;
    transition: var(--transition-fast);
    color: var(--white);
    font-size: var(--font-size-xs);
}

.task-checkbox input[type="checkbox"]:checked + .checkmark {
    background: var(--success-color);
    border-color: var(--success-color);
}

.task-checkbox input[type="checkbox"]:checked + .checkmark i {
    opacity: 1;
}

/* Task Content */
.task-content {
    flex: 1;
}

.task-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: var(--spacing-2);
    line-height: 1.4;
}

.task-description {
    color: var(--gray-600);
    margin-bottom: var(--spacing-3);
    line-height: 1.5;
}

.task-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-3);
}

.task-date {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    color: var(--gray-500);
    font-size: var(--font-size-sm);
}

.task-date i {
    color: var(--gray-400);
}

.task-actions {
    display: flex;
    gap: var(--spacing-2);
}

.action-btn {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: var(--font-size-sm);
}

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

.edit-btn:hover {
    background: #2563eb;
    transform: scale(1.1);
}

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

.delete-btn:hover {
    background: #dc2626;
    transform: scale(1.1);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--spacing-16) var(--spacing-8);
    color: var(--gray-500);
}

.empty-icon {
    font-size: 4rem;
    color: var(--gray-300);
    margin-bottom: var(--spacing-4);
}

.empty-state h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-2);
    color: var(--gray-600);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    background: var(--white);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-2xl);
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: scale(0.9) translateY(-20px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-6);
    border-bottom: 1px solid var(--gray-200);
}

.modal-header h3 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--gray-800);
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
}

.close-btn {
    width: 32px;
    height: 32px;
    border: none;
    background: var(--gray-100);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
    color: var(--gray-500);
}

.close-btn:hover {
    background: var(--gray-200);
    color: var(--gray-700);
}

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

.form-group {
    margin-bottom: var(--spacing-5);
}

.form-group label {
    display: block;
    font-weight: 600;
    color: var(--gray-700);
    margin-bottom: var(--spacing-2);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-3);
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    transition: var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-actions {
    display: flex;
    gap: var(--spacing-3);
    justify-content: flex-end;
    margin-top: var(--spacing-6);
}

/* Toast */
.toast {
    position: fixed;
    top: var(--spacing-6);
    right: var(--spacing-6);
    background: var(--success-color);
    color: var(--white);
    padding: var(--spacing-4) var(--spacing-6);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    display: none;
    z-index: 1001;
    animation: toastSlideIn 0.3s ease-out;
}

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

@keyframes toastSlideIn {
    from {
        opacity: 0;
        transform: translateX(100%);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.toast-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-container {
        padding: var(--spacing-4);
    }
    
    .header-content {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .stats-section {
        width: 100%;
        justify-content: space-between;
    }
    
    .stat-card {
        flex: 1;
        min-width: 100px;
    }
    
    .form-container {
        flex-direction: column;
    }
    
    .input-group {
        min-width: auto;
    }
    
    .task-meta {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .modal-content {
        width: 95%;
        margin: var(--spacing-4);
    }
    
    .form-actions {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .logo-text h1 {
        font-size: var(--font-size-2xl);
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .filter-tabs {
        width: 100%;
    }
    
    .filter-btn {
        flex: 1;
        text-align: center;
    }
}