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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.app-container {
    background: white;
    width: 100%;
    max-width: 440px;
    border-radius: 16px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0,);
    padding 0.25: 32px;
    animation: slideUp 0.5s ease-out;
}

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

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.app-header h1 {
    font-size: 28px;
    font-weight: 600;
    color: #1a1a2e;
}

.task-counter {
    font-size: 14px;
    color: #6b7280;
    background: #f3f4f6;
    padding: 6px 12px;
    border-radius: 20px;
    font-weight: 500;
}

.add-task-form {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
}

.task-input {
    flex: 1;
    padding: 14px 18px;
    border: 2px solid #e5e7eb;
    border-radius: 12px;
    font-size: 16px;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}

.task-input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.15);
}

.task-input::placeholder {
    color: #9ca3af;
}

.add-btn {
    width: 50px;
    height: 50px;
    border: none;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s, box-shadow 0.2s;
}

.add-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.add-btn:active {
    transform: scale(0.95);
}

.task-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.task-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 16px;
    background: #f9fafb;
    border-radius: 12px;
    animation: fadeIn 0.3s ease-out;
    transition: background 0.2s;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.task-item:hover {
    background: #f3f4f6;
}

.task-checkbox {
    width: 22px;
    height: 22px;
    border: 2px solid #d1d5db;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    flex-shrink: 0;
}

.task-checkbox:hover {
    border-color: #667eea;
}

.task-checkbox.checked {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-color: #667eea;
}

.task-checkbox.checked svg {
    opacity: 1;
}

.task-checkbox svg {
    opacity: 0;
    transition: opacity 0.2s;
}

.task-text {
    flex: 1;
    font-size: 16px;
    color: #374151;
    transition: color 0.2s;
    word-break: break-word;
}

.task-item.completed .task-text {
    text-decoration: line-through;
    color: #9ca3af;
}

.delete-btn {
    width: 32px;
    height: 32px;
    border: none;
    background: transparent;
    color: #9ca3af;
    cursor: pointer;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    opacity: 0;
}

.task-item:hover .delete-btn {
    opacity: 1;
}

.delete-btn:hover {
    background: #fee2e2;
    color: #ef4444;
}

.empty-state {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 48px 24px;
    color: #9ca3af;
    text-align: center;
}

.empty-state svg {
    margin-bottom: 16px;
    opacity: 0.5;
}

.empty-state p {
    font-size: 18px;
    font-weight: 500;
    margin-bottom: 4px;
    color: #6b7280;
}

.empty-state span {
    font-size: 14px;
}

.empty-state.visible {
    display: flex;
}