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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
}

/* Auth Section Styles */
.auth-section {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
}

.auth-container {
    background: white;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 15px 35px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 400px;
}

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

.auth-header h1 {
    font-size: 2rem;
    margin-bottom: 10px;
    color: #333;
}

.auth-header h1 i {
    margin-right: 10px;
    color: #4CAF50;
}

.auth-header p {
    color: #666;
    font-size: 1rem;
}

.auth-form {
    transition: all 0.3s ease;
}

.auth-form h2 {
    text-align: center;
    margin-bottom: 25px;
    color: #333;
    font-size: 1.5rem;
}

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

.form-group input {
    width: 100%;
    padding: 15px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
}

.auth-btn {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    margin-bottom: 20px;
}

.auth-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.auth-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

.auth-switch {
    text-align: center;
    color: #666;
    font-size: 0.9rem;
}

.auth-switch a {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
}

.auth-switch a:hover {
    text-decoration: underline;
}

/* Todo Section Styles */
.todo-section {
    width: 100%;
}

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

.header-content h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.header-content h1 i {
    margin-right: 10px;
    color: #4CAF50;
}

.header-content p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.logout-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    padding: 12px 16px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.logout-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.todo-input-section {
    background: white;
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 8px 25px rgba(0,0,0,0.1);
}

.input-group {
    display: flex;
    gap: 10px;
}

#todo-input {
    flex: 1;
    padding: 15px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

#todo-input:focus {
    outline: none;
    border-color: #667eea;
}

#add-btn {
    padding: 15px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

#add-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.todo-stats {
    display: flex;
    justify-content: space-around;
    margin-bottom: 20px;
    gap: 10px;
}

.stat {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: 10px;
    text-align: center;
    flex: 1;
    backdrop-filter: blur(10px);
}

.stat span {
    display: block;
    font-size: 1.5rem;
    font-weight: bold;
    color: #667eea;
}

.stat label {
    font-size: 0.9rem;
    color: #666;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.todo-filters {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 20px;
}

.filter-btn {
    padding: 10px 20px;
    background: rgba(255, 255, 255, 0.9);
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.filter-btn.active,
.filter-btn:hover {
    background: #667eea;
    color: white;
    transform: translateY(-2px);
}

.todo-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.todo-item {
    background: white;
    border-radius: 10px;
    padding: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    animation: slideIn 0.3s ease;
}

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

.todo-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.15);
}

.todo-item.completed {
    opacity: 0.7;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #888;
}

.todo-content {
    display: flex;
    align-items: center;
    gap: 15px;
}

.complete-btn {
    background: none;
    border: 2px solid #ddd;
    border-radius: 50%;
    width: 25px;
    height: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.complete-btn:hover {
    border-color: #4CAF50;
}

.complete-btn.completed {
    background: #4CAF50;
    border-color: #4CAF50;
    color: white;
}

.todo-text {
    flex: 1;
    font-size: 1rem;
    word-break: break-word;
}

.todo-actions {
    display: flex;
    gap: 5px;
}

.edit-btn,
.delete-btn {
    background: none;
    border: none;
    padding: 8px;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.edit-btn:hover {
    background: #e3f2fd;
    color: #2196F3;
}

.delete-btn:hover {
    background: #ffebee;
    color: #f44336;
}

.edit-form {
    display: flex;
    gap: 10px;
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px solid #eee;
}

.edit-input {
    flex: 1;
    padding: 10px;
    border: 2px solid #e0e0e0;
    border-radius: 5px;
    font-size: 1rem;
}

.edit-input:focus {
    outline: none;
    border-color: #667eea;
}

.save-btn,
.cancel-btn {
    padding: 10px 15px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.save-btn {
    background: #4CAF50;
    color: white;
}

.save-btn:hover {
    background: #45a049;
}

.cancel-btn {
    background: #f44336;
    color: white;
}

.cancel-btn:hover {
    background: #da190b;
}

.empty-state,
.loading {
    text-align: center;
    padding: 40px 20px;
    color: white;
}

.empty-state i,
.loading i {
    font-size: 3rem;
    margin-bottom: 20px;
    opacity: 0.7;
}

.empty-state h3,
.loading p {
    font-size: 1.2rem;
    margin-bottom: 10px;
}

.empty-state p {
    opacity: 0.8;
}

.hidden {
    display: none !important;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .auth-container {
        padding: 30px 20px;
    }
    
    .header-content h1 {
        font-size: 2rem;
    }
    
    .todo-stats {
        flex-direction: column;
    }
    
    .todo-filters {
        flex-wrap: wrap;
    }
    
    .filter-btn {
        flex: 1;
        min-width: 80px;
    }
    
    .todo-content {
        flex-wrap: wrap;
    }
    
    .todo-actions {
        margin-left: auto;
    }
}

@media (max-width: 480px) {
    .input-group {
        flex-direction: column;
    }
    
    #add-btn {
        width: 100%;
    }
    
    .edit-form {
        flex-direction: column;
    }
    
    .save-btn,
    .cancel-btn {
        width: 100%;
    }
    
    .auth-container {
        padding: 20px 15px;
    }
}